The teenager practiced driving from his apartment in San Diego down to Tijuana and back, on the orders of the criminals he was working for in Mexico. He rehearsed how he would respond to questions from U.S. border officers. He tracked when the drug-sniffing dogs took a break.

The men who were paying him had cut a secret compartment into his car big enough to fit several bricks of fentanyl. When they loaded it up for the first time and sent him toward the border, Gustavo, who was only 19 at the time, began to tremble.

At the checkpoint, he steadied himself like he had practiced, and calmly told the border officers that he was just heading home.

When Satnam Singh, a migrant fruit picker from India, chopped his arm off in an accident in June as he worked in fields near Rome, his boss, instead of taking Mr. Singh to a hospital, dropped him off in front of his house with part of his arm in a fruit basket. Shortly afterward, Mr. Singh died.

He had arrived in Italy in 2021 from the Punjab region on a temporary worker’s permit, then remained working illegally for more than two years, hoping in vain that an employer would legalize him, the police said. Instead, he found himself, like so many other migrants, ground up in a nearly feudal system that offers scant protections to some of Italy’s most necessary workers.

Mr. Singh’s death, at 31, stirred an uproar in Italy this summer, setting off a new round of soul-searching about the country’s conflicted relationship with immigrants.

Italy, with its aging and dwindling population, desperately needs foreign workers, but the public discourse has been dominated for years by talk of how to keep migrants away. Now, even those who had warned of “ethnic replacement” of Italians by foreigners, including Prime Minister Giorgia Meloni, have acknowledged the need for immigrant labor.

Her government has vowed to improve pathways for migrants to work legally in Italy, a system that experts and Ms. Meloni herself have said is rife with abuse, leaving many vulnerable to exploitation and blackmail.

“Satnam is the symbol of a system,” said Marco Omizzolo, a sociologist who for years has focused on migrant workers in the vast Agro Pontino farmlands in the central Lazio region, where Mr. Singh died.

Ms. Meloni called Mr. Singh’s death “disgusting,” saying it “does not reflect” Italy. She has tried to draw a sharp line between regular and irregular migration by cracking down on illegal arrivals by boat while also significantly increasing the number of work permits for migrant laborers.

In reality, the distinction between regular and irregular migrants remains blurry, experts said.

Many migrants, like Mr. Singh, come on seasonal contracts but then remain and work illegally in the country once those permits expire. Others come under the promise of a contract, but are never given one as the government’s current quotas for legal migrant workers do not bind employers to hire the migrants they bring in.

“In Italy, legal quotas end up fueling the illegal ones,” said Natale Forlani, the president of Italy’s National Institute for Public Policy Analysis, a public research institute overseen by the Labor Ministry. He added that for now, “Italy does not have a regular immigration policy worthy of the name.”

Francesco Fasani, an economist who focuses on migration at the University of Milan, called Italy’s entry system a “legal fiction.”

“Everyone knows that migrants come and work illegally,” he said.

Being already in the country, with no contract and sometimes with no permit, the workers are easy prey for unscrupulous employers. Mr. Singh’s story was emblematic of the risks and rampant abuses many migrant laborers face, experts said.

“If a whole society accepts that slaves exist,” said Gianfranco Schiavone, a leading expert on Italy’s migration law, “we can’t complain if one master is more evil than the others.”

In the Agro Pontino, the region about an hour south of Rome where Mr. Singh died, large numbers of Sikh workers from India pick kiwis, watermelons and zucchinis. The farmland there was reclaimed from malaria-infected swamps under Mussolini.

Mussolini also founded several cities in the region, and hard-right sympathies remain firmly rooted there. In the cafes among geometric, Fascist-style buildings, workers routinely refer to their bosses as “padrone,” which roughly translates as “master.”

Numerous investigations have revealed how workers are generally paid a few euros an hour, with contracts that grossly underrepresent the hours they work or with no papers at all. Employers have been known to seize the workers’ documents to keep them beholden to them. Middlemen, sometimes immigrants themselves, keep a large part of the workers’ slim salaries in exchange for backbreaking work in the fields and filthy housing.

Occasionally, an especially horrific act of abuse puts the system under a harsh new light, but the outcry fades and the exploitation continues.

Mr. Singh’s treatment, according to the account provided by Lt. Col. Michele Meola of the Carabinieri police, was particularly cruel. Mr. Singh was working with a plastic-wrap machine in June when his arm got stuck in it. A good chunk of it was completely smashed, Colonel Meola said.

Afterward, Mr. Singh’s boss drove him and his partner, Soni Soni, 26 — who was also working in the fields — to their house. She later testified in court that their boss “threw” Mr. Singh from his van, leaving his head bleeding, as well, according to her lawyer, Gianni Lauretti.

The defense lawyers for Mr. Singh’s boss, Antonello Lovato, said in a statement on Tuesday that a witness, employed by Mr. Lovato, said in court that Mr. Singh had spontaneously decided to use the plastic-wrap machine and that it was Ms. Soni who had asked Mr. Lovato to take Mr. Singh home.

Ms. Soni instead said that she had urged Mr. Lovato to take Mr. Singh to the hospital, according to her lawyer, Mr. Lauretti. Ms. Soni cried for help, and eventually an ambulance came, but it was too late. Mr. Singh died in a hospital soon after.

Mr. Singh’s boss, who had gone back to his farm to wash the blood from his van, was arrested in July, Colonel Meola said. Ms. Soni has received a residence permit while the investigation is underway.

After Mr. Singh’s death, Italian investigators inspected dozens of companies in the area and found irregularities among half of the workers they checked. Most were migrants, they said in a statement, some were even minors.

Similar practices span Italy. This summer, the police in the northern city of Verona said they had freed 33 people from “slavery.” The workers said in a statement that two Indian middlemen had lured them with the promise of seasonal labor and a 17,000 euro contract, or nearly $19,000. When they arrived, they worked for 10 to 12 hours a day seven days a week while receiving no payment to extinguish their supposed debt.

Critics say that such abuses are driven in part by a lack of checks, organized crime and ruthless profiteering. But the tenor of the public discourse around immigration in Italy has also made it harder to put in place the pragmatic steps the Italian government is trying to take, they say.

“The contradictions are everywhere,” said Matteo Villa, a researcher who focuses on migration at the Institute for International Political Studies, a research center based in Milan. “This transition doesn’t work if you keep telling people that we don’t want them.”

Today, Italy and Europe pay millions to North African countries like Libya and Tunisia to keep migrants away, and Ms. Meloni has credited the arrangements for a drop in the numbers of arrivals to Italy this year.

The strategy has attracted praise from other world leaders, but also criticism after reports that Tunisia was abandoning thousands of migrants in the desert, and that migrants had suffered violence, forced labor and exploitation in detention centers in Libya.

Ms. Meloni has also struck an agreement with Albania that allows Italy to send migrants who are rescued in the Mediterranean to detention centers there while their asylum claims are considered. That facility is scheduled to be opened in the coming weeks.

In the Agro Pontino, many migrant laborers said they believed that a feeling of superiority and impunity drove their employers’ attitudes.

Saiful Islam, 36, a Bangladeshi immigrant who lives in the area, summed up their reasoning this way: “‘You are an immigrant, you should be content with whatever you get.’”

Hassan Nasrallah, who led the militant Hezbollah organization in Lebanon for more than three decades and built it into a domestic political force and potent regional military power with ballistic missiles that could threaten Tel Aviv, was killed on Friday in heavy Israeli airstrikes just south of Beirut. He was 64.

Both Hezbollah and Israel announced his death on Saturday. Israeli officials had said that Mr. Nasrallah was the target of the attack, which rocked the area known as the Dahiya, a dense urban area south of the capital, with such violent force that residents fled in fear as a giant mushroom cloud rose over the city.

For almost two decades, since Hezbollah fought a monthlong war against Israel in 2006, Mr. Nasrallah had largely avoided public appearances and eschewed using a telephone out of concern that he would be assassinated.

In recent weeks, Israel had carried out repeated airstrikes in the same area to kill other top Hezbollah commanders, including some founding members who had been with the organization since it was established in the early 1980s to fight the Israeli occupation of southern Lebanon.

Mr. Nasrallah took over the group in 1992, at 32, after an Israeli rocket killed his predecessor. Over the years, his black beard turned white beneath the black turban that marked him as a revered Shiite Muslim cleric and a sayyid, a man who can trace his ancestry back to the Prophet Muhammad.

Throughout his career, he stuck to his central message: that Israel was a foreign and threatening presence in the region that needed to be removed, and that it was the job of every Muslim to contribute to the struggle.

In Lebanon, Mr. Nasrallah developed a force of thousands of grass-roots fighters — schoolteachers and butchers and truck drivers — and used religion to inspire them to fight until death, analysts say, telling them they would have a guaranteed spot in heaven.

As the head of the strongest militia that Iran helped build in the region — and one of the most heavily armed nonstate forces in the world — Mr. Nasrallah extended the group’s reach well beyond Lebanon. Hezbollah fighters were instrumental in shoring up the government of another ally, President Bashar al-Assad, next door in Syria when it was threatened by a popular uprising that started in 2011. Designated a terrorist organization by the United States, Hezbollah has helped to train Hamas fighters as well as militias in Iraq and Yemen.

In Lebanon, Mr. Nasrallah enjoyed tremendous devotion from Hezbollah’s Shiite Muslim base, who saw in him a charismatic religious and political leader and military strategist who had dedicated his life to “resistance,” or the fight against Israel and American influence in the Middle East.

For the Israelis, he was a hated terrorist who represented a perpetual threat on their northern border, and over the years, he displayed a ruthlessness in pursuing his goals.

In his speeches, especially in the years before his public appearances diminished, he often echoed the fierce anti-Israel, anti-American rhetoric that had become a trademark of Iran’s Islamic revolution. “This is a cancerous presence,” he said of Israel during rally in 2013 to mark Jerusalem Day, an Iranian-inspired holiday dedicated to calling for the liberation of Jerusalem, which he did all the time, anyway. “We all know that the nature of cancer is to spread in the body, and to kill. And the only solution for cancer is to uproot it, to not surrender to it, and to not give it an opportunity.”

He often referred to Israel as “the Zionist entity” and maintained that Jewish people who arrived from other countries over decades should return to their nations of origin, and said that Israel be replaced by the state of Palestine, with equality for all residents.

“Israel represents a huge, permanent problem to all the states and the peoples in this region and their abilities, decisions, security, dignity, stability and sovereignty,” he said in the same 2013 speech.

Israeli officials and others often closely monitored his speeches for indications of what he planned to do.

He was known, according to Arab tradition, as Abu Hadi or father of Hadi. His eldest son, Hadi, was 18 when he died in September 1997 in a firefight with the Israelis. The moniker was a reminder of Mr. Nasrallah’s personal credibility and commitment to the fight. He is believed to be survived by his wife and four other children, including one daughter.

“He is sort of the physical embodiment of this cause. He sacrificed his son, his whole life,” said Amal Saad, a Hezbollah expert and lecturer in political science and international relations at Cardiff University. “People see him as this heroic, almost mythical figure who embodies all the attributes of justice and liberation.”

Yoel Guzansky, who served on Israel’s National Security Council and is now a senior fellow at the Institute for National Security Studies, described Mr. Nasrallah as both “a horrific killer” and “very intelligent.”

“He’s a strategist,” Mr. Guzansky said, before Mr. Nasrallah’s death was announced, adding that he had a deep understanding of Israeli politics that he used to try to sway the Israeli public to pressure their government. “He’s a master in what he’s doing.”

In 1983, suicide bombing attacks against first the U.S. Embassy in Beirut, then the barracks of American and French peacekeepers, killed at least 360 people, including 241 American service members. The murderous attacks were claimed by the Islamic Jihad Organization, considered a precursor to Hezbollah, and some of those suspected of planning it later became top commanders under Mr. Nasrallah.

In the hierarchical rankings of Shiite Muslim clergy, Mr. Nasrallah was a rather ordinary hojatolislam, one step below an ayatollah, and far below a mujtahid, or “source of emulation,” to be followed as a guide. He was believed to live modestly and rarely socialized outside Hezbollah’s ruling circles.

Mr. Nasrallah was one of the Arab world’s most distinctive orators, with a robust command of classical Arabic that he spiced with common Lebanese phrases. He laced his speeches with references to restoring lost Arab virility, a message that resonated across a region long suffering from a sense of impotence in the face of Israel and its powerful Western backers.

He came across as less dour than most Shiite clerics, partly because of his roly-poly figure, a slight lisp and a propensity to crack jokes. He never pushed hard-line Islamic rules, like veils for women in the neighborhoods that Hezbollah controls. Analysts attributed that to his exposure in his youth to many of Lebanon’s 17 religious sects and his desire not to isolate Lebanese outside of Hezbollah’s religious Shiite base.

He could be by turns avuncular and menacing.

Walid Jumblatt, the chieftain of the Druse sect and at times an outspoken critic of Mr. Nasrallah, once said he found the combination unsettling. “Sometimes the eyes of people betray them,” he said. “When he’s calm, he’s laughing. He’s very nice. But when he’s a little bit squeezed, he looks at you in the eyes fiercely with fiery eyes.”

The state within a state that Mr. Nasrallah helped to build with Iranian and expatriate financing as Lebanon struggled to emerge from a long civil war that ended in 1990 included hospitals, schools and other social services. In a country where the government struggled to keep the lights on and to collect the garbage, Hezbollah’s ability to organize accounted for a great deal of its efficacy and helped build its popularity.

In 2000, he gained new respect in Lebanon and beyond after years of guerrilla warfare forced the Israeli military to withdraw from a strip of southern Lebanon that it had controlled since it invaded the country in 1982.

In 2005, Prime Minister Rafik Hariri was assassinated by a huge suicide truck bomb in downtown Beirut. An international tribunal later indicted four members of Hezbollah, although ultimately only one was convicted in absentia. The killing was believed to have been organized by the Syrian government, which had been determined to thwart Mr. Hariri’s attempts to loosen the grip of Syria’s security forces on the country. Mr. Nasrallah warned Lebanese against cooperating with the tribunal.

The 2006 war, which Hezbollah set off by capturing two Israeli soldiers during a cross-border raid, raged for 34 days and caused widespread destruction and more than 1,100 deaths in Lebanon and 150 in Israel, but ended up bolstering Hezbollah’s regional standing.

The war ended with both sides declaring victory, and Hezbollah was lauded across the Arab world for fighting Israel head on and not losing. After the war, fans in Cairo, Damascus and other Arab capitals publicly displayed his photograph, and Mr. Nasrallah apologized to the Lebanese, saying that he would have avoided the war if he had known how destructive it would be. It was a rare statement of contrition for an Arab leader.

The United Nations Security Council passed a resolution that called for Hezbollah to disarm and for only a United Nations force and the Lebanese Army to deploy in southern Lebanon. Hezbollah rejected both demands, arguing that its arms were necessary to defend Lebanon against Israel. Critics called that stance a pretext for Hezbollah to keep the weapons that gave the group an outsize role in Lebanese politics.

In 2008, the Lebanese government moved to dismantle Hezbollah’s private communications network, a move that Mr. Nasrallah called a declaration of war on the group. Hezbollah fighters stormed West Beirut, routing fighters that backed the government in deadly street battles. Hezbollah’s turning its guns on other Lebanese was seen as a betrayal by the group’s critics and taken as proof that its purpose was not solely to fight Israel.

In sending fighters to defend Mr. Assad, a fellow ally of Iran, Mr. Nasrallah framed the conflict as part of the fight against Israel, even once claiming that “the road to Jerusalem” ran through Aleppo, a Syrian city 180 miles in the other direction. Arab critics blasted Hezbollah for fighting and imposing painful sieges on fellow Muslims while keeping Lebanon’s border with Israel calm.

Mr. Nasrallah initially tried to keep himself above Lebanon’s messy domestic politics, but that proved impossible as members of his party accepted cabinet positions and won more and more seats in Parliament. His standing took another blow in Lebanon in 2019, when protesters took to the streets to decry the country’s notoriously corrupt ruling class amid a painful economic collapse. Some demonstrators hung effigies of Mr. Nasrallah alongside those of other political figures, considering him part of the group whose selfish policies had ruined the country.

After a large stockpile of ammonium nitrate stored in a hangar in the port of Beirut blew up in August 2020, killing more than 120 people and damaging nearby neighborhoods, Mr. Nasrallah worked with Lebanon’s politicians to freeze the official investigation as the inquiry focused on some of Hezbollah’s political allies. The inquiry was never completed.

Born in 1960 in Beirut, Mr. Nasrallah grew up in a mixed neighborhood of impoverished Christian Armenians, Druse, Palestinians and Shiites where his father had a vegetable stand. The eruption of the civil war in 1975 forced the family to flee to their native village in the south.

The oldest of nine children and deeply devout from a young age, he decamped for the most famous Shiite hawza, or seminary, in Najaf, Iraq. He fled in 1978 one step ahead of Saddam Hussein’s secret police, returning to Lebanon to join Amal, then a new Shiite militia. He became its Bekaa Valley commander in his early 20s.

He studied briefly at a seminary in Qum, Iran, in 1989, and considered Iran’s Islamic Revolution led by Ayatollah Ruhollah Khomeini in 1979 to be the best model for Shiites to end their historic second-class status in the Muslim world.

Security around Mr. Nasrallah has long been extraordinary. When he granted a rare interview to The New York Times in 2002, the reporter and photographer were blindfolded and driven around the southern suburbs of Beirut for a short time before the meeting. His security team then inspected absolutely everything that would enter the room, even unscrewing the pens to make sure that they contained only ink.

Hezbollah began firing into Israel on Oct. 8 last year, a day after the war in Gaza started, and Hezbollah and Israel had engaged in tit-for-tat exchanges ever since. Despite the constant threat of a full-scale war, Mr. Nasrallah appeared reluctant to unleash Hezbollah’s full arsenal, estimated at tens of thousands of missiles, given that many Lebanese, weary of grinding economic problems and general chaos, might have penalized the party for dragging them into an unwanted war. It also seemed that Iran hoped to avoid expending an arsenal devised as its forward line of defense against any Israeli attack.

On Sept. 19, in his last televised remarks, he blamed Israel for the exploding pagers and walkie-talkies that killed dozens of his foot soldiers and wounded several thousand more in the days before. “This retribution will come,” he said. “Its manner, size, how and where — these are things we will certainly keep to ourselves, in the narrowest circles even among us.”

At least 66 people have died and 69 were missing in Nepal after incessant monsoon rains unleashed flooding and landslides across the small Himalayan nation, which has been increasingly pummeled by the effects of climate change.

Rescue operations were underway for thousands of people, Nepali officials said on Saturday. At least 60 have been injured, and the death toll was expected to rise, the officials said.

More than half of the dead were from the Kathmandu Valley, which includes Kathmandu, the capital. Highways into the city were closed.

Binod Ghimire, a senior superintendent of police, said that more than 5,000 police personnel equipped with helicopters, rafts, ropes and vehicles had been deployed for rescue operations.

Rescuers have evacuated more than 3,000 people, but flooding victims complained of delays. A video circulating on social media showed people who were swept away by the floods after waiting on the roof of a hut for hours.

Many parts of the country were without power. “Several districts are disconnected from communication, so we are struggling to compile loss of lives and properties,” said Dan Bahadur Karki, a spokesman for the Nepal Police.

The authorities asked people to stay indoors if possible. The rainfall was expected to stop by Sunday.

The flood disaster occurred just as Nepalis were preparing to celebrate the Hindu festival of Dashain, which is scheduled to begin on Thursday. Hindu devotees travel for days to far-flung villages to obtain the blessings of their elders.

Nepal, with a population of about 30 million, is the fourth-most-vulnerable country to climate change, according to UNICEF. In recent years, the frequency of disasters — including the bursting of glacial lakes as temperatures rise — has increased, claiming more lives.

Local news media, citing the National Disaster Risk Reduction and Management Authority, recently reported that 225 people have died and 49 have gone missing in disasters related to the monsoon season, which runs from June to September.

At least 17 people from a single family were killed when gunmen attacked two homesteads in South Africa early Saturday, the police said, adding to a rising number of mass shootings in the country.

Gunmen opened fire on two separate homesteads as the victims slept, the police said. The victims all belonged to one family, who had gathered for a traditional ceremony in a village outside Lusikisiki, a town in rural Eastern Cape Province, the police told journalists later in television interviews.

Thirteen people were killed in one homestead, the police said, adding that all but one of the victims were women. Six people survived, among them a 2-month-old baby, Brig. Athlenda Mathe, a police spokeswoman, told a local television station. Another victim is in the hospital in critical condition.

In a second homestead, all four people inside a single house were killed, according to Ms. Mathe.

The authorities have started a manhunt, as the town reels from the killings. Police footage showed dirt roads cordoned off, with forensics teams and uniformed officers working across the two homesteads, one consisting of several houses, painted orange with white pillars, the other made up of modest blue-and-white houses. Stunned community members gathered on the other side of the police cordon, and remained on the scene as rain poured down.

“This is the first time we’ve witnessed something like this,” Lwando Nonkonyana, a spokesman for the local municipality, said in a telephone interview. “And it’s a shock to the area.”

Police officials, who had gathered in another part of the province for a crime-fighting campaign, pointed to the worryingly high number of illegal firearms and high rates of gun violence in the region.

In the past four months, the police have seized more than 430 illegal firearms, including automated rifles, most of them confiscated in the Eastern Cape, Senzo Mchunu, the police minister, said during the news briefing on Saturday. Officers were treating the mass killing as a priority, he added.

“It’s an intolerably huge number of people,” Mr. Mchunu said.

South Africa has for years recorded high rates of violent crime, and the police and experts have noted an increasing number of mass shootings in the past few years.

In January 2023, gunmen killed eight people at a birthday party in Gqeberha, a coastal city in the Eastern Cape Province. In April last year, gunmen stormed a house and killed 10 people at a homestead outside the city of Pietermaritzburg, in the east of the country. And in July 2022, at least 19 people were shot dead in multiple taverns, including in Johannesburg’s Soweto township.

Crime statistics released by the government in August showed that murder rates had increased in four of South Africa’s nine provinces, driven largely by gun violence.