Marjayoun, Lebanon. Israeli strikes Monday on Lebanon killed more than 490 people, including more than 90 women and children, Lebanese authorities said, in the deadliest barrage since the 2006 Israel-Hezbollah war. The Israeli military warned residents in southern and eastern Lebanon to evacuate ahead of its widening air campaign against Hezbollah.

Thousands of Lebanese fled the south, and the main highway out of the southern port city of Sidon was jammed with cars heading toward Beirut in the biggest exodus since 2006.

Lebanon's health ministry said the strikes killed 492 people, including 35 children and 58 women, and wounded 1,645 people -- a staggering one-day toll for a country still reeling from a deadly attack on communication devices last week.

In a recorded message, Israeli Prime Minister Benjamin Netanyahu urged Lebanese civilians to heed Israeli calls to evacuate, saying “take this warning seriously.”

“Please get out of harm’s way now,” Netanyahu said. “Once our operation is finished, you can come back safely to your homes.”

Israel's military spokesman, Rear Adm. Daniel Hagari, said the army will do “whatever is necessary” to push Hezbollah from Lebanon’s border with Israel.

Hagari claimed Monday’s widespread airstrikes had inflicted heavy damage on Hezbollah. But he would not give a timeline for the operation and said Israel was prepared to launch a ground invasion of Lebanon if needed.

“We are not looking for wars. We are looking to take down the threats,” he said. “We will do whatever is necessary to do to achieve this mission."

Hagari said Hezbollah has launched some 9,000 rockets and drones into Israel since last October, including 250 on Monday alone.

The military said Israeli warplanes struck 1,600 Hezbollah targets Monday, destroying cruise missiles, long- and short-range rockets and attack drones. The spokesman said many were hidden in residential areas, showing photos of what he said were weapons concealed in private homes.

“Hezbollah has turned southern Lebanon into a war zone,” he told a news conference.

Israel estimates Hezbollah has some 150,000 rockets and missiles, including guided missiles and long-range projectiles capable of striking anywhere in Israel.

Earlier Monday evening, the Israeli military said it had carried out a targeted strike in Beirut. It did not give details. Lebanon’s state-run National News Agency reported three missiles hit southern Beirut's Beir al-Abed neighborhood. Hezbollah's Al-Manar TV said six people were wounded.

Lebanese Health Minister Firass Abiad said the earlier strikes hit hospitals, medical centers and ambulances. The government ordered schools and universities to close across most of the country and began preparing shelters for the displaced.

Some strikes hit residential areas in the south and the eastern Bekaa Valley. One hit a wooded area as far away as Byblos, more than 80 miles (130 kilometers) from the border north of Beirut.

Israel said it was expanding the airstrikes to include areas of the valley along Lebanon’s eastern border with Syria. Hezbollah has long had an established presence in the valley, where the group was founded in 1982 with the help of Iran’s Revolutionary Guards in the wake of Israel’s invasion and occupation of Lebanon.

Israel’s military chief, Lt. Gen. Herzi Halevi, said Israel was preparing its “next phases” of operations against Hezbollah, and that its airstrikes were “proactive,” targeting Hezbollah infrastructure built over the past 20 years.

Halevi said the goal was to allow displaced Israelis to return to their homes in northern Israel.

Meanwhile, Hezbollah said it fired dozens of rockets toward Israel, including at military bases. It also targeted for a second day the facilities of the Rafael defense firm, headquartered in Haifa.

The evacuation warnings were the first of their kind in nearly a year of steadily escalating conflict and came after a particularly heavy exchange of fire Sunday. Hezbollah launched around 150 rockets, missiles and drones into northern Israel in retaliation for strikes that killed a top commander and dozens of fighters.

The increasing strikes and counterstrikes have raised fears of all-out war, even as Israel battles Hamas in Gaza and tries to negotiate the release of scores of hostages taken in Hamas' Oct. 7 attack. Hezbollah has vowed to continue its strikes in solidarity with Hamas, a fellow Iran-backed militant group.

A spokeswoman for President Joe Biden said the administration was concerned about what’s happening between Israel and Hezbollah in Lebanon and insisted that getting a cease-fire deal between Israel and Gaza was key to easing tensions in the region.

“It’s in everyone’s interest to resolve it quickly and diplomatically,” White House Press Secretary Karine Jean-Pierre told reporters traveling with Biden to New York, where he is to deliver his final address to the UN General Assembly on Tuesday.

A State Department official, who spoke to reporters on condition of anonymity to discuss the private diplomatic efforts, said the US and numerous other countries were keen to present an “off-ramp” for both Israel and Hezbollah to reduce tensions and prevent an all-out war.

The US has “concrete ideas” for restoring calm that it will present to allies and partners at this week's UN General Assembly, the official said. He wouldn't detail what the “concrete ideas” were because he said they had yet to be presented to allies and partners for what he termed a “stress test” for their likelihood of success.

UN peacekeepers in southern Lebanon near the Israeli border, meanwhile, have stopped their patrols and are staying in their bases “given the volume of exchange of fire,” a UN spokesman said. Stéphane Dujarric told reporters that UN Secretary-General António Guterres was “alarmed” at the escalating violence and large number of civilian casualties reported in Lebanon.

Monday's death toll far surpassed that of Beirut’s devastating port explosion in 2020, when hundreds of tons of ammonium nitrate stored in a warehouse detonated, killing at least 218 people and wounding more than 6,000.