WASHINGTON

US President Joe Biden warned Tuesday against the possibility of "all-out war" as Israel continues to pound Lebanon with airstrikes that have killed over 550 people, prompting Hezbollah to ramp up retaliatory strikes.

"Full-scale war is not in anyone's interest. Even as the situation has escalated, a diplomatic solution is still possible," Biden said in an address to the UN General Assembly in New York. "In fact, it remains the only path to lasting security to allow the residents from both countries to return to their homes and the border safely."

Biden said he and his senior officials are "working tirelessly" to achieve that end.

Israel dramatically escalated its airstrikes across Lebanon on Monday in airstrikes it says targeted Hezbollah. The attacks have killed at least 558 people so far, including 95 women and 50 children, according to official tallies.

"The majority of the victims in the Israeli attacks since Monday morning are defenseless civilians in their homes. This refutes the enemy's claim it was targeting fighters," Lebanese Health Minister Firas Abiad said.

Thousands of residents in Lebanon's south have fled the massive bombardment in the hopes of finding safety elsewhere in the nation.

Hezbollah has responded to the strikes by stepping up its rocket fire on Israel, including by striking deep into the country.

The Lebanese group, which operates as both a political party and paramilitary in Lebanon, said it targeted Israel’s Rafael Electronics Company, which is located north of Haifa, as well as the reserve headquarters of the Northern Corps and logistics base of the Galilee Formation in the Ami'ad camp.

Hezbollah and Israel have been engaged in cross-border warfare since the start of the Israeli war on Gaza, which has killed over 41,400 people, mostly women and children. The war began last October, nearly a year ago, following a Hamas-led cross-border attack on Israel that killed 1,139 people and led to 250 others being taken back to Gaza as hostages.

Turning to Gaza, Biden said "now is the time" for Israel and Hamas to finalize the terms of a cease-fire and hostage deal he laid out in May, saying it will "ease the suffering in Gaza and end this war."

"I've met with the families of those hostages. I've grieved with them. They're going through hell. Innocent civilians in Gaza are also going through hell, thousands and thousands killed, including aid workers; too many families dislocated, crowding in the tents, facing a dire humanitarian situation," said Biden.

"They didn't ask for this war that Hamas started," he added.