KHAN YOUNIS, Gaza Strip (AP) — The U.S. worked to break a deadlock over delivering aid to millions of increasingly desperate civilians in the Gaza Strip, which has been besieged and under assault by Israel since a brutal attack by Hamas militants, as U.S. President Joe Biden prepared to head to the region.

Israeli airstrikes continued to pound Gaza early Tuesday, killing dozens of people in the besieged enclave’s south, where Israel told civilians from the north to seek shelter ahead of an expected ground offensive.

Wounded people were rushed to the hospital after heavy attacks outside the southern Gaza cities of Rafah and Khan Younis, Gaza residents reported. Basem Naim, a senior Hamas official and former health minister, reported that 27 people were killed in Rafah and 30 were killed in Khan Younis.

A Palestinian man inspects the remains of a destroyed house hit by an Israeli airstrike in town of Khan Younis, southern Gaza Strip, Tuesday, Oct. 17, 2023. (AP Photo/Mohammed Dahman)

An Associated Press reporter saw around 50 bodies brought to Nasser Hospital in Khan Younis since early Tuesday. Family members came to claim the bodies, wrapped in white bedsheets, some soaked in blood.

An airstrike in Deir al Balah reduced a house to rubble, killing nine members of the family living there. Three members of another family that had evacuated from Gaza City were killed in a neighboring home. The dead included one man and 11 women and children. Witnesses said there was no previous warning before the strike.

Israel has sealed off Hamas-ruled Gaza and hammered it with unrelenting airstrikes since the militant attack on southern Israel last week killed 1,400 people, mostly civilians. Dozens of Israelis and citizens of other countries were taken captive and brought to Gaza by militants.

Israeli strikes have killed at least 2,778 people and wounded 9,700 others in Gaza, according to the Health Ministry. The strikes have not stopped Hamas militants from continuing to barrage Israel with rockets launched from Gaza.

Airstrikes, dwindling supplies, and Israel’s mass evacuation order for the north of the Gaza Strip has thrown the tiny territory’s 2.3 million people into upheaval and caused increasing desperation.

More than 1 million Palestinians have fled their homes, and 60% are now in the approximately 14-kilometer-long (8 mile) area south of the evacuation zone, the U.N. said.

Aid workers warned that the territory was near complete collapse as hospitals were on the verge of losing electricity, threatening the lives of thousands of patients, and hundreds of thousands of people searched for bread. With taps dry, many rationed the little clean water available and others resorted to drinking dirty or sewage-filled water, risking disease.

At the Rafah crossing, Gaza’s only connection to Egypt, truckloads of aid were waiting to go into the tiny, densely populated territory, and trapped civilians — many of them Palestinians with dual nationalities — were hoping desperately to get out.

Mediators were trying to reach a cease-fire to open the border, which shut down last week after Israeli airstrikes. An agreement appeared to have been reached Monday, but Israel denied reports of a cease-fire in Rafah, which would be needed to open the gates. On Tuesday morning, they were still closed.

An Egyptian official said Tuesday that Egypt and Israel agreed that the aid convoys at the border would travel into Israel for inspection at the Kerem Shalom crossing between Gaza and Israel. The aid would then be allowed into Gaza. A brief humanitarian ceasefire would take place and foreign nationals would be allowed to exit Gaza via Rafah, the official said, speaking on condition of anonymity because he was not allowed to speak with the media.

U.S. Secretary of State Antony Blinken, who visited Israel for the second time in a week on Monday after a six-country tour through Arab nations, said in Tel Aviv that the U.S. and Israel had agreed to develop a plan to enable humanitarian aid to reach civilians in Gaza. There were few details, but the plan would include “the possibility of creating areas to help keep civilians out of harm’s way.”

Gen. Erik Kurilla, the head of U.S. Central Command, arrived in Tel Aviv for meetings with Israeli military authorities ahead of a Biden visit planned for Wednesday to signal White House support for Israel. Biden will also travel to Jordan to meet with Arab leaders amid fears the fighting could expand into a broader regional conflict as fighting intensified along Israel’s border with Lebanon.

In addition to the dead, some 1,200 people across Gaza are believed buried under the rubble, alive or dead, health authorities said. Emergency teams struggled to rescue people while cut off from the internet and mobile networks, running out of fuel and exposed to unceasing airstrikes. On Monday Israeli warplanes struck the headquarters of the Civil Defense in Gaza City, killing seven paramedics. Another 10 medics and doctors have been killed on the job, health authorities said.

Israel also evacuated towns near its northern border with Lebanon, where the military has exchanged fire repeatedly with the Iranian-backed Hezbollah group.

The military said it killed four militants wearing explosive vests who were attempting to cross into the country from Lebanon on Tuesday morning. Video from a reconnaissance drone the army shared showed the militants near the border wall before they were targeted, causing an explosion. No group immediately claimed responsibility.

“Whoever approaches the border with Lebanon will be killed,” said Israeli military spokesman, Rear Adm. Daniel Hagari.

Israel has warned Lebanon it will strongly retaliate against attacks from across the border.

Israel fought a vicious monthlong war with Hezbollah in 2006 that ended in a stalemate and a tense detente between the two sides.

Speaking to the Israeli Knesset, Prime Minister Benjamin Netanyahu warned Iran and Hezbollah, “Don’t test us in the north. Don’t make the mistake of the past. Today, the price you will pay will be far heavier.”

Soon after he spoke, the Knesset floor was evacuated as rockets headed toward Jerusalem. Sirens in Tel Aviv prompted U.S. and Israeli officials to take shelter in a bunker, officials said.

Iran’s foreign minister, meanwhile, warned that “preemptive action is possible” if Israel moves closer to a ground offensive. Hossein Amirabdollahian’s threat followed a pattern of escalating rhetoric from Iran, which supports Hamas and Hezbollah.

The Israeli military said Monday at least 199 hostages were taken into Gaza, more than previously estimated. Hamas said it was holding 200 to 250 hostages.

Hamas’ military wing released a hostage video showing a dazed woman having her arm wrapped with bandages. The woman, who identified herself as Mia Schem, 21, rocked slightly as she spoke, the sound of explosions reverberating in the background.

The plight of the hostages has dominated the Israeli media since the attack, with interviews with their relatives playing on television almost constantly. Israeli officials have vowed to maintain the siege of Gaza until the hostages are released.

In Gaza, more than 400,000 displaced people in the south crowded into schools and other facilities of the U.N. agency for Palestinians. The agency said it has only 1 liter of water a day for each of its staff members trapped in the territory.

Israel opened a water line into the south for three hours that benefitted only 14 percent of Gaza’s population, the U.N. said.