Hundreds of soldiers and police officers converged this week on a former security compound in the western Syrian city of Latakia, heeding the call of the country’s new rulers to relinquish their ties to the ousted regime of President Bashar al-Assad.

During its decades-long rule, the Assad government built a brutal security apparatus, detaining, torturing and executing opponents. Last week, the rebel coalition that overthrew him said it would hunt down senior officials implicated in crimes, while rank-and-file conscripted soldiers would receive amnesty.

More than 600 people came when the so-called reconciliation center first opened on Sunday in Latakia, in a province that has been an Assad stronghold. Many more followed on Monday, the line extending the length of the large security compound.

They hoped to clear their names and settle their status, though the centers are just the starting point and the full process to do so remains unclear.

Online and on television, the Syrian transitional government, led by the rebel group Hayat Tahrir al-Sham, called for former soldiers, military officers and even medical workers in the military to hand over their IDs, weapons and vehicles.

Supervisors at the Latakia center, one of the first in the country, said similar ones had opened or would open in provinces across Syria.

After hours of waiting — and jostling to get a number — some of the men finally made it inside.

At a desk near the front entrance, a police officer with the new Syrian government wrote down each person’s name and a number in blue ink to create a temporary ID. After that, each arrival was told to stand against the wall and hold the number in front, for a mug shot.

The former soldiers and police officers handed in their weapons through two windows along a wall, protected by metal security bars. One man had brought a Soviet-era machine gun, but it was too big to fit through the opening so he had to hand it over at the front door.

Every few seconds came the sound of men cocking guns and checking to ensure their bullet chambers were empty.

Mohammad Mustafa, a 26-year-old security officer with Hayat Tahrir al-Sham’s interior ministry, dressed all in black, including a beanie and a face mask, stood in the middle of a room that under Mr. al-Assad was used for interrogations. Now, it had become an impromptu weapons depository.

The new authorities had collected dozens of AK-47s, handguns and other weapons, sorting them in piles by type.

This was just part of the process. Inside one of the intake rooms, Warrant Officer Othman Karoom, 40, until recently a traffic police officer in the rebel-controlled city of Idlib, filled out spreadsheets with the details of each person.

“What was your specialty?” he asked, as 28-year-old Mohammad al-Jarrah sat down in a ratty chair in front of his desk.

“Cannons,” Mr. al-Jarrah said, adding quickly in his defense: “I was a conscript.”

“How much did you shell Maraat Misrin and Jebel al Zawiyah?” Mr. Karoom said, mentioning his hometown and a nearby town. “He whose hands have blood on them … ”

“I swear to God, those who have blood on their hands,” Mr. al-Jarrah replied, “They will all be known.”

As the former rebels worked inside gathering information, the lines grew longer outside, the men — and a few women — hoping for their chance at amnesty.

Waiting hours in the cold, a group of men yelled and pushed forward, trying to force their way into the security building. A police officer of the new government rushed toward them, his rifle pointed. Soon order was restored, as police officers pushed many back outside the main gate.

Several people were injured in the crush. They were allowed to stay inside the complex to get processed.

It could be a while before any of the former police officers and soldiers know their fate.

Mr. Mustafa of the interior ministry said each person would need to report back in three months to a security headquarters to be fully investigated.

“Right now, we don’t have time,” he said.

An oasis stretched far into the desert, a vast sea of emerald stalks and scarlet poppy flowers that grew to the horizon.

The Taliban operated openly, running a social experiment unlike anything in the country. Tens — then hundreds — of thousands of people flocked here to escape the war and grow poppy, fleeing the American efforts to wipe out the crop.

The Taliban opened a trauma hospital to treat their wounded and earned a fortune, not just from opium, but also from methamphetamines and taxes on goods moving in and out of Afghanistan, bringing them millions upon millions of dollars every month.

During the war, this remote district became a laboratory for a future Taliban state, providing money for the war and a sanctuary for the men fighting it.

All that has changed. The Taliban boom town is rapidly going bust.

The same insurgents who embraced opium to help finance their war have put an end to it, ordering a ban that has all but cleared Afghanistan of poppy and other illicit drugs.

What the United States and its allies failed to do in two decades of war, the Taliban has managed in two years of peace. In an area where poppy once dominated the landscape, barely a stalk remains.

The Russian authorities said on Wednesday that they had detained a suspect in the killing of a senior military officer, Lt. Gen. Igor Kirillov, a major development in the most prominent political assassination case in the country since the start of the war in Ukraine.

The suspect, a 29-year-old citizen of Uzbekistan whose name was not released, was detained in a village outside Moscow, a spokeswoman for Russia’s prosecutor’s office said.

The spokeswoman said the detainee had confessed that Ukrainian intelligence agencies recruited him to kill General Kirillov, 54, who was in charge of the Russian military’s nuclear and chemical weapons protection forces.

An official with Ukraine’s security service, known as the S.B.U., said on Tuesday that Ukraine had been responsible for the killing, which took place in central Moscow on Tuesday. He discussed sensitive intelligence on the condition of anonymity.

The detainee traveled to Moscow and placed a bomb under a scooter near the general’s home, the prosecutor’s office spokeswoman said.

He also installed a camera inside a parked rental car that transmitted the general’s movements to intelligence agents in Ukraine, she added. He was promised $100,000 and safe passage to Europe for carrying out the plot, she said. An aide to the general was also killed when the bomb was detonated.

“We got more proof that the Kyiv regime does not stop at anything, including terrorism,” Dmitri S. Peskov, the Kremlin’s spokesman, told reporters on Wednesday. He added that President Vladimir V. Putin had offered condolences to the general’s family.

General Kirillov was the most senior Russian official to have been assassinated away from the battlefield since the start of the war. Previous assassination attempts have targeted Russian propagandists and more junior military officers.

On Wednesday, Russia’s foreign ministry spokeswoman, Maria Zakharova, said the country would raise the killing of General Kirillov at the scheduled meeting of the United Nations Security Council on Friday.

“We are certain that all the organizers and executors of the murder of Igor Kirillov will be found and punished, whoever they are and wherever they may be,” Ms. Zakharova said.

The general’s killing is the latest embarrassment for Russia’s domestic intelligence agency, the F.S.B., which has assumed greater power and influence since the start of the war in Ukraine nearly three years ago.

The F.S.B. has blamed Ukraine for most terrorist attacks and major accidents in the country since the invasion, usually without providing evidence.

Critics have said such tactics have allowed Russia’s intelligence agencies to deflect the blame for their own failures to detect domestic threats, often associated with Islamist groups.

Analysts have said that the F.S.B. has been blindsided by several attacks associated with Islamism, including the deadliest terrorist attack in Russia in more than a decade, because they were excessively focused on combating Ukrainian sabotage and terrorism operations.

The admission from a Ukrainian intelligence official that Kyiv orchestrated the killing of General Kirillov suggests that the F.S.B. has now failed to protect the country’s leadership from precisely such a threat.

After the killing, some Russian ultranationalist commentators accused the country’s secret services of ineptitude.

“The enemy’s secret services are acting with impunity on the territory of the Russian Federation, and above all in the capital and the metropolises,” Yuri Kotenok, a prominent Russian war correspondent, wrote on social media on Tuesday. “This is mayhem.”

The suspect’s citizenship of Uzbekistan could be consequential. A combination of nationalist war fervor and the participation of citizens of Central Asian countries in recent terrorist attacks have led to a rise in xenophobia and a tightening of immigration laws in Russia.

The backlash against Central Asian immigrants, by far the largest group of foreign workers in Russia, has come at a time of record labor shortages.

Russia’s business groups have been concerned that new measures against migrants would tighten the labor market further, with destabilizing effects for the economy.

Milana Mazaeva contributed reporting from Istanbul.

Shortly before the first domestic flight since Bashar al-Assad’s fall landed at Aleppo International Airport late Wednesday morning, the final preparations were still being made. Workers rushed to remove about a dozen empty ammunition boxes, gas masks and helmets from a grassy patch next to the runway.

When the Syrian Air flight from Damascus landed, more than an hour behind schedule, it was greeted by a large crowd of journalists and a phalanx of security personnel, including military police officers and civil defense workers, standing by in case anything went wrong.

But its arrival was otherwise smooth — a sign, the rebels who ousted Mr. al-Assad as president 10 days ago hope, that Syria’s new transitional government will be able to run the country. As part of that, they hope to provide war-weary civilians with basic services, including domestic and international flights.

“We consider this a big accomplishment — we are coming to rebuild this country,” said Anas Rustum, who was appointed to oversee the Aleppo airport by Hayat Tahrir al-Sham, the rebel group that led the offensive against the Assad government.

He said they were open to welcoming flights from all countries and airlines, touting “these results you are seeing in front of your eyes,” as the just-landed Airbus A320 sat on the tarmac behind him.

The flight was a chance for Syria’s new leaders to demonstrate not only technical competence in aviation but their ability to provide security: On the roof of the terminal building, a security officer armed with a rifle watched over the scene below.

The flight marked a new chapter for Syria as well as the airport itself. Throughout Syria’s nearly 14-year civil war, the civilian facility was used by the Assad government to stage attacks on rebels and civilians living in rebel-held areas.

Ahmed Ibrahim, an airport control tower operator for nearly three decades, said the Assad forces had positioned a machine gun atop the control tower to fire on nearby neighborhoods.

When the rebels captured Aleppo late last month, the airport’s employees were afraid, Mr. Ibrahim said. But they were soon reassured as the rebel leadership called on all airport staff members to return to work.

He said that domestic and international aviation could be a symbol of the new, post-Assad Syria.

“We’re hoping for there to be an opening to other countries,” he said.