A quarter of Lebanon’s territory is now under Israeli military evacuation orders, according to the United Nations, in an indication that Israel’s air and ground campaign against Hezbollah militants could spark another humanitarian crisis in the Middle East.

President Joe Biden and Israeli Prime Minister Benjamin Netanyahu spoke Wednesday for the first time since August, their offices said. The weekslong silence between the two leaders highlighted their souring relationship as Israel intensified its war in the Gaza Strip despite Biden’s calls for de-escalation.

Details of the call were not immediately available. It came after Israel’s defense minister, Yoav Gallant, delayed a trip to Washington where he had been expected to discuss Israel’s potential response to Iran’s missile attack last week. Gallant said Wednesday that he had postponed the trip at the request of Netanyahu, who told him he first wanted to speak with Biden.

In Gaza, a large Israeli operation in the northern part of the Palestinian territory left dozens of people dead and threatened to shut down three hospitals over a year into the war with Iran-backed Hamas, Palestinian officials and residents said.

Residents of Jabaliya, a refugee camp dating to the 1948 war surrounding Israel’s creation, said thousands of people are trapped at home since the operation began Sunday, as Israeli jets and drones fly and troops battle militants in the streets.

The Lebanon assessment released Wednesday by the U.N. human rights commissioner came as smoke from airstrikes bloomed over parts of southern Lebanon, where Lebanese news reports said Israeli warplanes had carried out more attacks in and around the cities of Tyre and Saida.

Iran-backed Hezbollah said Wednesday that it was engaged in skirmishes with Israeli troops in southern Lebanon. Its fighters launched another barrage of missile attacks at the northern Israeli city of Haifa on Wednesday afternoon, after the militant group warned that it would render the city uninhabitable if the Israeli military continued its offensive in Lebanon.

Sirens sounded in Haifa Bay and were followed by about 40 rockets, according to the Israeli military, which said many were intercepted by air defenses. Explosions were heard in Haifa and surrounding villages, and Israeli emergency services officials reported that they were treating six people for shrapnel injuries after a rocket hit a road near Haifa.

A rocket fired from Lebanon killed two people in the northern Israeli town of Kiryat Shmona, and another six were stabbed and wounded in the city of Hadera on Wednesday. Police said the attacker was “neutralized” and later clarified he had been arrested.

Hezbollah claimed the strike on Kiryat Shmona, saying it targeted “a gathering of enemy forces.” Ofir Yehezkeli, the acting mayor, said the two killed were a couple walking their dogs.

The Israeli airstrikes have continued more than a week after the start of a ground invasion of southern Lebanon that the military has described as “limited,” saying it aims to clear the border area of Hezbollah fighters, weapons and tunnels that threaten northern Israel’s residents.

“To the people of south Lebanon, be careful!” an Israeli military spokesperson, Avichay Adraee, warned in a post in Arabic. He said Israeli forces were continuing “to attack Hezbollah sites in and near your village, and for your own safety you are prohibited from returning to your homes until further notice.”

The Israeli calls for evacuations have sent residents of more than 100 villages and urban areas of southern Lebanon fleeing north, according to the United Nations, which said that the Israeli warnings now cover a quarter of Lebanon’s land area, including areas in the Bekaa Valley and along the Syrian border. More than 600,000 people in the country of 5.4 million are now displaced, the U.N. warned.

The air and land attacks in the south followed another night of Israeli airstrikes in the densely populated areas near Beirut where Hezbollah holds sway. Although a barrage of attacks overnight into Wednesday appeared to be less intense than previous days, Lebanon’s death toll continued to rise, with the Health Ministry saying 36 people died and more than 100 were injured nationwide over the previous day.

More than 2,100 people have been killed and more than 10,000 injured since Israel intensified its air campaign against Hezbollah leadership in late September. The attacks have killed Hezbollah’s longtime leader, Hassan Nasrallah, and several other top figures.

Israeli officials said Tuesday that Nasrallah’s presumed successor, Hashem Safieddine, had also been killed in a recent strike, although Hezbollah has not confirmed his death.

Associated Press contributed.