Iran’s supreme leader on Saturday threatened “a crushing response” to Israeli strikes on his country, as the Pentagon said it would deploy additional resources to the region in the coming months.

Tehran initially appeared to play down the damage caused by Israeli strikes inside Iran late last month, raising hopes that it might de-escalate the situation rather than pursue a new cycle of retaliation. But in recent days, Iranian officials have changed their tone.

Iran’s supreme leader, Ayatollah Ali Khamenei, has the authority as commander in chief to order strikes on Israel. In a statement posted online, he said on Saturday that Israel and the United States would “definitely receive a crushing response” for actions against Iran.

His remarks echoed two Iranian officials who this past week said that Iran would retaliate, with one telling state news media that a response would be “definite” and a second saying Iran would launch “a fierce, tooth-breaking” response.

After years of avoiding direct military clashes, Iran and Israel have been locked in an escalating monthslong cycle of retaliation that has drawn in their allies and proxies, bringing the region to the brink of an all-out war.

The Pentagon in late September extended the deployment of an aircraft carrier strike group in the Gulf of Oman to deter Iranian attacks and shoot down any ballistic missiles fired into Israel.

To maintain those kinds of capabilities in the region when that carrier, the U.S.S. Abraham Lincoln, returns to its home port, the Pentagon announced late Friday that a new deployment of ships and land-based warplanes would head to the region.

Maj. Gen. Pat Ryder, the Pentagon press secretary, said that Defense Secretary Lloyd J. Austin III had ordered the deployment of fighter aircraft, ballistic missile defense destroyers and B-52 long-range bombers to assist in the defense of Israel and other U.S. interests in the region.

“Secretary Austin continues to make clear that should Iran, its partners, or its proxies use this moment to target American personnel or interests in the region, the United States will take every measure necessary to defend our people,” General Ryder said in a statement.

The United States has already bolstered its military presence in the region as tensions rise. It sent an advanced missile defense system, called the Terminal High Altitude Area Defense system, or THAAD, and the 100 American troops needed to operate it, to Israel.

Their arrival less than two weeks ago was the first time that U.S. troops had been deployed to Israel for such a mission since the start of the war last October.

The Biden administration sent key envoys, including the C.I.A. director, to the Middle East this week in hopes of generating some momentum in talks to end Israel’s war against Hamas in Gaza and its spiraling conflict with Hezbollah in Lebanon. Both groups are Iranian proxies. But those efforts have floundered, and the fighting has continued unabated.

On Saturday, Lebanon’s health ministry said that one person had been killed and 15 others had been wounded by an Israeli airstrike in the Dahiya, a densely populated area south of Beirut where Hezbollah holds sway. The previous day, heavy Israeli strikes killed at least 52 people in the central part of the country, the Lebanese authorities said, and seven people in northern Israel were killed by Hezbollah rocket attacks.

The Israeli military said on Saturday that its forces had struck more than 120 sites in both Lebanon and Gaza since the day before, including an airstrike in the Lebanese city of Tyre that it claimed killed two Hezbollah commanders. It also said troops were conducting ground operations in northern, central and southern Gaza.

In central Israel early on Saturday, a rocket strike hit Tira, an Arab-majority town in central Israel, and injured several people. The Israeli military said that three rocket launches had been detected overnight from Lebanon, including at the region that includes Tira. Another 30 launches from Lebanon were detected on Saturday afternoon, the military said.

Magen David Adom, Israel’s emergency medical service, said 11 people were wounded in Tira, with most of the injuries minor to moderate. A photograph and a video posted by the emergency service showed the top floor of a building with its walls blown out.

Hezbollah started striking Israel in solidarity with Hamas, its ally in Gaza, after the Oct. 7 Hamas-led attacks last year prompted Israel to launch a war against the group in Gaza.

After nearly a year of cross-border attacks that primarily landed in the border region, Hezbollah in recent months has taken aim deeper inside Israel. The militant group launched missiles at the densely populated Tel Aviv area in September and October. Those were intercepted with no reported injuries or damages.

Victoria Kim, Rawan Sheikh Ahmad and John Ismay contributed reporting.

Germany’s three-party coalition government, wracked by infighting and policy paralysis over a stagnant economy, is teetering on the brink of collapse.

It does not look likely to last until the next scheduled elections in September 2025 and could fall imminently over a nasty budget debate that comes to a head this month, analysts say. The main political parties are already laying out their campaign positions, and coalition leaders are barely talking.

The growing rift became more evident Friday evening, when a leaked position paper by the leader of one coalition party called for a fundamental economic overhaul that contradicts government policies, and is meant to cut costs.

The 18-page economic paper was written by Christian Lindner, the leader of the pro-market liberal Free Democratic Party.

Mr. Lindner wants to cut some social service payments, drop a special “solidarity tax” intended to help fund German reunification, and follow European Union climate regulations rather than more ambitious national ones — all demands that his coalition partners are highly unlikely to accept.

After coalition parties lost votes in three state elections in September, Mr. Lindner warned that the coming months would become the “autumn of decisions.” And he has suggested that if the coalition did not work in his favor, his party could quit the government of Chancellor Olaf Scholz.

“The way in which the government is currently presenting itself and also the unclear basic direction — neither corresponds to my expectations of government conduct,” Mr. Lindner said Thursday in an online interview. “The situation as it is now cannot continue.”

The German economy shrank last year and barely escaped recession this year. Consumer and business confidence is low, and the German export model has been severely challenged by China’s own slowdown and by sanctions on Russia.

What may keep the coalition together is the American presidential election.

If former President Donald J. Trump is re-elected, he is likely to pose formidable challenges for European security and trade. It would be a bad time for Germany, a central player in Europe, to be run by a caretaker government with little ability to make major decisions and preoccupied with its domestic politics, analysts warned.

Elected in 2021, the coalition was immediately confronted with the Russian invasion of Ukraine.

It managed the initial crisis well, but is increasingly split over policy. Mr. Scholz’s Social Democrats have been trying to preserve the country’s generous welfare state even as the economy slowed; the Greens are pressing to fight climate change despite the financial costs; and the Free Democrats are demanding adherence to Germany’s strict constitutional limits on budget deficits and debt.

The three key leaders of the coalition, Mr. Scholz; Robert Habeck of the Greens, the economic minister; and Mr. Lindner, the finance minister, are barely speaking to one another, according to local media reports.

“Lindner wants out of the coalition, he just doesn’t know how yet,” read a headline on Friday in Bild, the country’s hugely popular tabloid.

At the same time, an opposition legislator, Norbert Röttgen of the Christian Democrats, and others have argued that the shock of a Trump victory, and what it could entail for Ukraine, NATO and European security, means that “you would need a German government that is willing and able to lead from popular consensus and a new mandate.”

Germany’s financial and military support for Ukraine has been crucial for Kyiv, second only to the American contribution. Mr. Trump often criticizes Germany for its supposed deficit in overall military spending, and as president he tried to pull thousands of American troops out of the country.

If Mr. Trump is elected and decides to reduce or stop aid to Ukraine or undermines credibility in NATO, a functioning German government is considered vital to any coordinated European response.

For a long time, the assumption was that the government would stay together until the next federal election, especially given the weak performance of the coalition partners in opinion polls. The opposition Christian Democrats are well ahead in the polls and the party’s leader, Friedrich Merz, would most likely become chancellor if a vote were held now.

But Mr. Lindner’s liberal Free Democratic Party, which won nearly 12 percent of the vote in 2021, has sunk in recent polls below the 5 percent threshold necessary to have seats in the next Bundestag, or Parliament. He has been hinting strongly that if he broke from the government over the budget, he could run a new campaign on a platform of defending taxpayers against the big-spending coalition parties.

If he does break away later this month, there could be new elections as early as March.

But Mr. Lindner could also be trying to press for advantage in the budget talks. His own party is divided, and coalition collapses are rare in Germany.

The gap in the budget is under 10 billion euros, or almost $11 billion, hardly a large sum. Still, Mr. Lindner’s choice to reopen an agreement on pension reform has infuriated Mr. Scholz, and both sides have taken strong public positions on the issue that will be hard to pull back. Mr. Lindner objects to the cost, given an aging population and slower economic growth.

Even if the government survives until next September, it could remain essentially paralyzed on key issues, especially on how to produce sustained economic growth.

The government’s inability to agree on central policies is damaging all the coalition parties, said Christian Mölling of the German Council on Foreign Relations. The arguments about policy, “are no longer rational political arguments but look more and more like an emotional, personal thing,” he said.

With Mr. Scholz and President Emmanuel Macron of France so weak, “Europe is completely without a leader, there is no one,” he said. “The most stable government is possibly Italy.”

Germans have reasons to be concerned about their slowing economy, whether it is the crisis over Volkswagen’s plans to shut factories, the break with Russia over energy after Moscow invaded Ukraine, or China’s declining imports. So even if Germany’s economy is in reasonable shape compared to neighboring France or even Japan, that may be little consolation.

According to the latest poll by the public broadcaster ARD, only 14 percent said they were satisfied with the work of the coalition, and 54 percent wanted early elections.