No one in the family had much time for grief. Darabeh’s wife, brother and mother, all medical professionals, went back to work. His father, a doctor too, led prayers in the yard of Darabeh’s hospital Tuesday, his voice reedy with anguish as he gazed down at his eldest son, swaddled in a white sheet.

As another doctor embraced him, Darabeh’s father repeated, “May Allah protect your kids, May Allah protect your kids,” before his voice trailed off.

Israel announced a “complete siege” of the Gaza Strip on Monday, two days after an unprecedented assault by Hamas militants, who killed more than 1,000 people, many of them civilians.

“You wanted hell — you will get hell,” Israeli general Ghassan Aliyan said Tuesday, foreshadowing a full-scale invasion of Gaza, which people fear could happen at any moment.

Israel has pounded Gaza with airstrikes for four days, killing more than 900 people, according to the Palestinian Health Ministry. Residents bracing for a ground assault say they have nowhere to go.

More than 180,000 people have been displaced, according to the U.N. Office for the Coordination of Humanitarian Affairs, a number it said is expected to rise.

Most people are taking shelter in schools operated by UNRWA, the United Nations Relief and Works Agency.

“People are looking for that blue flag — for them, the blue of the U.N. is a sign of safety, and they’re taking their families there,” Tamara al-Rifai, UNRWA’s director of external relations and communications, told Al Jazeera.

Although U.N. buildings are protected from attacks by international law, at least 14 UNRWA buildings have sustained damage, including a school, she said.

The siege and the incessant bombardment has disrupted every facet of life in Gaza. More than 2 million people live in the strip, which is twice the size of D.C. but has three times as many people. Eighty percent of residents live in poverty, and over 90 percent do not have access to clean water.

Israeli Prime Minister Benjamin Netanyahu advised Gazans on Sunday to leave immediately “because we will operate forcefully everywhere.”

But Israel has closed the Erez Crossing, Gaza’s lone pedestrian pathway into the country. Rafah — the only functioning crossing with Egypt and the only way out for Gazans — has been hit repeatedly by the Israeli military, including again on Tuesday, forcing its closure.

Analysts say the Egyptian government is probably worried about the domestic consequences of a mass influx of Palestinians. In his first comments on the conflict Tuesday, President Abdel Fattah el-Sisi said national security is his top priority, “and I will not neglect it under any circumstances.”

Israeli Defense Minister Yoav Gallant’s siege order cut off what little water, electricity, food and fuel Israel allows into the strip, where people have lived under a crippling blockade since 2007.

Internet is intermittent at best, as is electricity and cellular service. Darabeh’s family friend, who spoke on the condition of anonymity because of security concerns, said she is too afraid to leave her house.

“Strikes are falling from everywhere,” she said. Her mouneh, the Arabic term for one’s reserve of dried and canned goods, “is enough for me to live for three days,” she said.

The Israel Defense Forces said they have hit more than 1,300 targets across Gaza since the start of the aerial campaign, including weapons storage facilities and command and control centers belonging to Hamas and Palestinian Islamic Jihad. Video of the strikes released by the IDF show buildings exploding so quickly that, from above, they look almost like twinkling lights. The targets erupt in fireballs, collapsing and swallowing nearby structures.

The strikes have wrought massive destruction along major thoroughfares and in civilian areas. Footage filmed and shared by local journalists show whole neighborhoods in ruins, with downtown Gaza a gray-toned ghost town.

At least one hospital and one medical center have been knocked out of service by Israeli bombardment, the Health Ministry said Tuesday, adding that around a dozen ambulances have been hit and are no longer operational.

Doctor Medhat Abbas, the director of Gaza’s largest hospital, al-Shifa, told The Post that these were the worst conditions he had seen in Gaza “in my entire life, and I’m 60 years old.”

Strikes near the hospital blew out windows and collapsed the ceiling in its nursery, said Mohammed Zaqout, the director general of hospitals in Gaza’s Ministry of Health.

“No hospital has been spared from the repeated aggression on Gaza,” he said in a video on Facebook.

At least six journalists have been killed in the enclave since Saturday, according to the Committee to Protect Journalists. Hisham al-Nwajha, a correspondent for the Gaza-based news outlet Khabar Press, had been posting updates on his Facebook page. He vowed that media coverage “is still continuing around the clock and will not stop.”

His final post, in the early hours of Tuesday, said airstrikes were targeting the Remal neighborhood. His wife posted that her husband had been injured and was undergoing surgery.

“Pray for him,” she pleaded.

His news outlet later announced that he had died from his injuries. “[My] groom, my life, the love of my heart and the companion of my path, has beat me to the gardens of bliss,” his wife wrote.

The U.N. High Commissioner for Human Rights Volker Turk described the situation on Tuesday as a “powder keg,” urging states with influence to step in and help defuse it.

“The imposition of sieges that endanger the lives of civilians by depriving them of goods essential for their survival is prohibited under international humanitarian law,” Turk said in a statement, adding that any restrictions that cannot be justified by military necessity may amount to collective punishment.

Mkheimer Abusada, a prominent Gazan political analyst, said he starts to panic as the bombings get louder and closer. Like most people in Gaza, he has nowhere to go.

“What is needed is [a] safe passage, a humanitarian corridor,” he said. “We need an immediate truce. Now. Two hours. Six hours. A one-day truce.

“We can live without electricity. Without fuel. With little food. But the most important thing now is safe area.”

Miriam Berger in Jerusalem and Claire Parker in Cairo contributed to this report.