Families fleeing the escalating conflict in Lebanon have poured into Syria in growing numbers, waiting for hours in heavy traffic to reach the relative safety of another war-torn country.

U.N. officials estimated that thousands of Lebanese and Syrian families had already made the journey. Those numbers are expected to grow as Israel targets southern and eastern Lebanon in an aerial bombardment that local officials say has killed more than 600 people this week, at least a quarter of them women and children.

Qatar, a mediator in the Gaza war, said on Thursday there was no direct link between talks for a truce in Gaza and an international push for an immediate ceasefire between Lebanon's Hezbollah and Israel.

"I'm not aware of a direct link, but obviously both mediations are hugely overlapping when you are talking about the same parties, for the most part, that are taking part," foreign ministry spokesman Majed al-Ansari told reporters.

An Israeli airstrike in Lebanon hit a building housing Syrian workers, killing 23 of them and wounding eight other people, Lebanon’s state-run news agency reported Thursday.

The National News Agency said the strike late Wednesday occurred in the country's northeast, near the ancient city of Baalbek, in Lebanon's eastern Bekaa Valley, which runs along the Syrian border.

The sandy beaches of Haifa, Israel's third-largest city, are empty. Businesses are shutting early, and many restaurants are closed. The only places filling up, as the threat of a wider war with Hezbollah mounts, are public bomb shelters.

Haifa, a seaside city of nearly 300,000 people, is the cultural and economic capital of northern Israel. It has increasingly come into Hezbollah 's sights since fighting with Israel escalated this week and residents are bracing for what many fear will be the worst round of violence since a war nearly two decades ago pounded the city with rockets.

Iranian Foreign Minister Abbas Araghchi said Wednesday that the Middle East was facing a "full-scale catastrophe" and warned Tehran would back Lebanon by "all means" if Israel escalated its offensive against Hezbollah.

"The region is on the brink of a full-scale catastrophe. If unchecked, the world will face catastrophic consequences," he said at the United Nations, adding that Iran would "stand with the people of Lebanon with all means."

The Israeli military said on Thursday it hit around 75 "Hezbollah targets" in Lebanon during the night, including ammunition depots of the Lebanese armed group.

"Overnight, the IDF (Israeli military)... struck approximately 75 terror targets" belonging to Hezbollah "in the area of Bekaa and in southern Lebanon, including weapons storage facilities, ready-to-fire launchers" as well as militants and other infrastructure, the military said in a statement.

The U.S., France and other allies jointly called Wednesday for an immediate 21-day cease-fire to allow for negotiations in the escalating conflict between Israel and Hezbollah that has killed more than 600 people in Lebanon in recent days.

The joint statement, negotiated on the sidelines of the U.N. General Assembly in New York, says the recent fighting is "intolerable and presents an unacceptable risk of a broader regional escalation."

Israel's far-right Finance Minister Bezalel Smotrich on Thursday rejected a proposal for a 21-day ceasefire in Lebanon and called for the "crushing" of the Lebanese armed group Hezbollah.

"The campaign in the north should end with a single result: crushing Hezbollah and elimination of its ability to harm the residents of the north," Smotrich said on social media platform X, adding that the ceasefire proposed by the U.S. and its allies would give Hezbollah time to "reorganize".

U.S. President Joe Biden warned Wednesday of the possibility of an "all-out war" in the Middle East as Israel put troops on alert for possible entry into Lebanon and the war in Gaza grinds on.

"An all-out war is possible," Biden told ABC chat show "The View." "What I think is, also, the opportunity is still in play to have a settlement that could fundamentally change the whole region."

The Biden administration is working on a new diplomatic initiative for a "pause" in the fighting in Lebanon and a resumption of negotiations on a Gaza hostage and ceasefire deal, two U.S. officials, one Israeli official and two sources with direct knowledge told U.S. news portal Axios.