GAZA CITY, Gaza Strip — Israeli airstrikes killed at least six people across the Gaza Strip and destroyed the home of an extended family early Wednesday.

Despite growing international pressure for a cease-fire, the military said it widened its strikes on militant targets in the Palestinian territory’s south to blunt continuing rocket fire from Hamas.

In a phone call with Netanyahu on Wednesday, President Joe Biden told Netanyahu "that he expected a significant de-escalation today on the path to a ceasefire," according to a readout of the call released by the White House.

Netanyahu rejected Biden's calls for a ceasefire on Wednesday, saying that while he appreciates Biden's support of Israel's right to self-defense, he is "determined to continue this operation until its goal is achieved," restoring peace and security to Israel's citizens.

Residents surveyed the piles of bricks, concrete and other debris that had once been the home of 40 members of al-Astal family in the southern Gaza town of Khan Younis. They said a warning missile struck the building five minutes before the airstrike, allowing everyone to escape.

Ahmed al-Astal, a university professor, described a scene of panic before the airstrike hit, with men, women and children racing out of the building. Some of the women didn't even have time to cover their hair with Muslim headscarves, he said.

“We had just gotten down to the street, breathless, when the devastating bombardment came,” he said. “They left nothing but destruction, the children’s cries filling the street. ... This is happening, and there is no one to help us. We ask God to help us.”

The Israeli military said it struck a militant tunnel network around the towns of Khan Younis and Rafah, with 52 aircraft hitting 40 underground targets. Gaza’s Health Ministry said a woman was killed and eight people were wounded in those strikes.

Hamas-run Al-Aqsa radio said one of its reporters was killed in an airstrike in Gaza City. Among the six killed Wednesday were also two people who died when warning missiles crashed into their apartment.

The latest strikes came as diplomatic efforts aimed at a cease-fire gathered strength and Gaza’s infrastructure, already weakened by a 14-year blockade, rapidly deteriorated. Medical supplies, water and fuel for electricity are running low in territory, on which Israel and Egypt imposed the blockade after the Islamic militant group Hamas seized power in 2007.

The Biden administration was privately encouraging Israel to wind down its bombardment of Gaza. Egyptian negotiators also were working to halt the fighting, and while they have not made progress with Israel, they were optimistic international pressure would force it to the table. Officials discussed the sensitive diplomacy on condition of anonymity.

But it was still unclear if or how soon those efforts would yield results. Prime Minister Benjamin Netanyahu said Israel hopes to restore quiet “quickly” but did not exclude the possibility of further escalation.

“You can either conquer them, and that’s always an open possibility, or you can deter them,” he told foreign ambassadors. “We are engaged right now in forceful deterrence, but I have to say, we don’t rule out anything.”

Military officials, meanwhile, said a mysterious explosion that killed eight members of a Palestinian family on the first day of the fighting was caused by a misfired rocket from Gaza. "This wasn’t an Israeli attack," said Lt. Col. Jonathan Conricus, a military spokesman.

The fighting began May 10 when Hamas fired long-range rockets toward Jerusalem after days of clashes between Palestinian protesters and Israeli police at the Al-Aqsa Mosque compound, a flashpoint site sacred to Jews and Muslims. Heavy-handed police tactics at the compound and the threatened eviction of dozens of Palestinian families by Jewish settlers had inflamed tensions.

At least 219 Palestinians have been killed in the current fighting, including 63 children and 36 women, with 1,530 people wounded, according to the Gaza Health Ministry, which does not break the numbers down into fighters and civilians. Hamas and Islamic Jihad say at least 20 of their fighters have been killed, while Israel says the number is at least 130. Some 58,000 Palestinians have fled their homes.

Twelve people in Israel, including a 5-year-old boy and a soldier, have been killed.

The Israeli military has launched hundreds of airstrikes it says are targeting Hamas’ militant infrastructure, while Palestinian militants have fired more than 3,700 rockets at Israel, with hundreds falling short and most of the rest intercepted. The rockets have reached a number of Israeli cities, including Tel Aviv, and have brought life to a standstill in areas near Gaza.

Israeli attacks have damaged at least 18 hospitals and clinics and destroyed one health facility, the World Health Organization said. Nearly half of all essential drugs have run out.

The Gaza Health Ministry said it had salvaged coronavirus vaccines after shrapnel from an Israeli airstrike damaged the territory's only testing facility, which also administered hundreds of vaccines. The operations were relocated to another clinic.

Dr. Majdi Dhair, head of preventive medicine at the ministry, said the territory was already struggling to recover from a coronavirus wave that hit in February, with more than 4,200 active cases. At least 986 people have died from COVID-19 in Gaza, which only has enough supplies to vaccinate some 55,000 people out of a population of 2 million.

Among the buildings leveled by Israeli airstrikes was one housing The Associated Press' Gaza office and those of other media outlets.

Israeli Prime Minister Benjamin Netanyahu alleged that Hamas military intelligence was operating in the building. Secretary of State Antony Blinken said Tuesday that Israel had given the U.S. information about the bombing, without elaborating.

The AP has called for an independent investigation of the attack. The news organization's president, Gary Pruitt, has said the AP had no indication Hamas was present in the building and that “this is something we check as best we can.”

The fighting — the worst since a 2014 war between Israel and Hamas — has ignited protests around the world and inspired Palestinians in Israel and the occupied territories to call a general strike Tuesday. It was a rare collective action that spanned boundaries central to decades of failed peace efforts. Israel captured the West Bank, east Jerusalem and Gaza in the 1967 Mideast war, territories the Palestinians want for their future state.

Although the strike was peaceful in many places, with shops in east Jerusalem’s usually bustling Old City markets shuttered, violence erupted in the occupied West Bank.

Hundreds of Palestinians burned tires in Ramallah, where the Palestinian Authority is headquartered, and hurled stones at an Israeli military checkpoint. Three protesters were killed and more than 140 wounded in clashes with Israeli troops in several cities, according to the Palestinian Health Ministry. The Israeli army said two soldiers were wounded in Ramallah by gunshots to the leg.