Israel and Lebanon-based Hezbollah militants began a ceasefire Wednesday in a major step toward ending nearly 14 months of fighting as a region on edge wondered whether it will hold.

Some celebratory gunshots could be heard in parts of Beirut’s southern suburbs, battered over the past two months, but no immediate violations of the ceasefire were reported.

Israel has said it will attack if Hezbollah breaks the agreement, and an Israeli military spokesman, in an Arabic-language X post in the first half-hour of the ceasefire, warned evacuated residents of southern Lebanon to not head home yet, saying the military remained deployed there.

The ceasefire calls for an initial two-month halt to fighting and requires Hezbollah to end its armed presence in southern Lebanon, while Israeli troops are to return to their side of the border. Thousands of additional Lebanese troopsand U.N. peacekeepers would deploy in the south, and an international panel headed by the United States would monitor compliance.

The ceasefire began at 4 a.m. Wednesday, a day after Israel carried out its most intense wave of airstrikes in Beirut since the start of the conflict that in recent weeks turned into all-out war. At least 42 people were killed in strikes across the country, according to local authorities.

The ceasefire does not address the devastating war in Gaza, where Hamas is still holding dozens of hostages and the conflict is more intractable.

There appeared to be lingering disagreement over whether Israel would have the right to strike Hezbollah if it believed the militants had violated the agreement, something Prime Minister Benjamin Netanyahu insisted was part of the deal but which Lebanese and Hezbollah officials have rejected.

Netanyahu supports ceasefire proposal with Hezbollah

Israel's security Cabinet approved the U.S.-France-brokered ceasefire agreement after Netanyahu presented it, his office said. President Joe Biden, speaking in Washington, called the agreement “good news” and said his administration would make a renewed push for a ceasefire in Gaza.

The Biden administration spent much of this year trying to broker a ceasefire and hostage release in Gaza but the talks repeatedly sputtered to a halt. President-elect Donald Trump has vowed to bring peace to the Middle East without saying how, and his team linked the deal to Trump's looming return to office.

Any halt to the fighting in Lebanon is expected to reduce the likelihood of war between Israel and Iran, which backs both Hezbollah and Hamas and exchanged direct fire with Israel on two occasions earlier this year.

Israel says it will ‘attack with might’ if Hezbollah breaks truce

Netanyahu presented the ceasefire proposal to Cabinet ministers after a televised address in which he listed accomplishments against Israel’s enemies. He said a ceasefire with Hezbollah would further isolate Hamas in Gaza and allow Israel to focus on its main enemy, Iran.

“If Hezbollah breaks the agreement and tries to rearm, we will attack,” he said. “For every violation, we will attack with might.”

Biden said Israel reserved the right to quickly resume operations in Lebanon if Hezbollah breaks the terms of the truce, but that the deal "was designed to be a permanent cessation of hostilities.”

Netanyahu’s office said Israel appreciated the U.S. efforts in securing the deal but “reserves the right to act against every threat to its security.”

Lebanon’s caretaker Prime Minister Najib Mikati welcomed the ceasefire and described it as a crucial step toward stability and the return of displaced people.

Hezbollah has said it accepts the proposal, but a senior official with the group said Tuesday it had not seen the agreement in its final form.

“After reviewing the agreement signed by the enemy government, we will see if there is a match between what we stated and what was agreed upon by the Lebanese officials,” Mahmoud Qamati, deputy chair of Hezbollah’s political council, told the Al Jazeera news network.

Israel cracks down on Palestinian citizens who speak out against the war in Gaza

“We want an end to the aggression, of course, but not at the expense of the sovereignty of the state," he said, referring to Israel's demand for freedom of action. “Any violation of sovereignty is refused.”

Warplanes bombard Beirut and its southern suburbs

Even as ceasefire efforts gained momentum in recent days, Israel continued to strike what it called Hezbollah targets across Lebanon while the militants fired rockets, missiles and drones across the border.

An Israeli strike on Tuesday leveled a residential building in central Beirut — the second time in recent days warplanes have hit the crowded area near downtown. At least seven people were killed and 37 wounded, according to Lebanon's Health Ministry.

Israel also struck a building in Beirut's bustling commercial district of Hamra for the first time, hitting a site around 400 meters (yards) from Lebanon’s Central Bank. There were no reports of casualties.

The Israeli military said it struck targets linked to Hezbollah's financial arm.

The evacuation warnings covered many areas, including parts of Beirut that previously were not targeted. Residents fled. Traffic was gridlocked, with mattresses tied to some cars. Dozens of people, some wearing pajamas, gathered in a central square, huddling under blankets or standing around fires as Israeli drones buzzed overhead.

Israeli military spokesman Avichay Adraee issued evacuation warnings for 20 buildings in Beirut's southern suburbs, where Hezbollah has a major presence, as well as a warning for the southern town of Naqoura where the U.N. peacekeeping mission, UNIFIL, is headquartered.

UNIFIL spokesperson Andrea Tenenti said peacekeepers will not evacuate.

Israeli forces reach Litani River in southern Lebanon

The Israeli military also said its ground troops clashed with Hezbollah forces and destroyed rocket launchers in the Slouqi area on the eastern end of the Litani River, a few kilometers (miles) from the Israeli border.

Under the ceasefire deal, Hezbollah is required to move its forces north of the Litani, which in some places is about 30 kilometers (20 miles) north of the border.

Hezbollah began firing into northern Israel on Oct. 8, 2023, saying it was showing support for the Palestinians, a day after Hamas carried out its attack on southern Israel, triggering the Gaza war. Israel returned fire on Hezbollah, and the two sides have exchanged barrages ever since.

Israel escalated its bombardment in mid-September and later sent troops into Lebanon, vowing to put an end to Hezbollah fire so tens of thousands of evacuated Israelis could return to their homes.

More than 3,760 people have been killed by Israeli fire in Lebanon the past 13 months, many of them civilians, according to Lebanese health officials. The bombardment has driven 1.2 million people from their homes. Israel says it has killed more than 2,000 Hezbollah members.

Hezbollah fire has forced some 50,000 Israelis to evacuate in the country’s north, and its rockets have reached as far south in Israel as Tel Aviv. At least 75 people have been killed, more than half of them civilians. More than 50 Israeli soldiers have died in the ground offensive in Lebanon.