Israeli officials described a “precise and targeted” mission aimed at the Hamas militants they accuse of operating a warren of tunnels beneath the al-Shifa Hospital complex, a charge the group denies. National Security Council spokesman John Kirby, citing intelligence sources, said Tuesday that Hamas and other militants “used some hospitals in the Gaza Strip, including al-Shifa, and tunnels underneath them, to conceal and support their military operations and to hold hostages.”

Palestinian officials called the storming of the hospital a “crime against humanity” that leaves terrified civilians to uncertain fates in a medical facility that already was running on fumes after days of intense bombardment by the encroaching forces.

The move immediately drew alarm from international humanitarian groups. The head of the World Health Organization, Tedros Adhanom Ghebreyesus, said the agency had “lost touch again with health personnel at the hospital” Wednesday morning and was “extremely worried” for the safety of the hospital and its patients. U.N. aid chief Martin Griffiths said he was “appalled” by the reports, adding: “Hospitals are not battlegrounds.”

The Biden administration said it would not comment on Israel’s military maneuvers but, in a statement just after the operation began, repeated President Biden’s remarks earlier this week that Gaza’s hospitals “must be protected.”

Hamas criticized the operation and blamed the White House for what it called a “green light” to enter the hospital and endanger civilians.

The Gaza Health Ministry said it received a warning from the Israel Defense Forces shortly before the early-morning operation, which many had viewed as inevitable since Israel said Hamas activity at the hospital was a top target in its war against the militants who carried out a deadly surprise attack in southern Israel on Oct. 7 that triggered the conflict.

Omar Zaqout, head of the emergency department, told Al Jazeera television that the hospital had endured a night of nonstop shooting and explosions before Israeli forces “blasted” into the compound, sending shrapnel into buildings where patients and displaced families were being housed.

“No one can even dangle a finger outside the window from the fear of the heavy shooting and the artillery shells,” Zaqout told the channel. “We lack the most basic of life necessities.”

The near-blackout conditions meant only a partial, murky look at what’s going on inside the compound. Phone numbers for medical staff rang with no answer or were disconnected. Reached by phone twice since the raid began Wednesday morning, plastic surgeon Ahmed al-Mokhallalati said he was hiding in Shifa’s main surgical building along with 15 of his colleagues. His summary of their status: “We are surviving.”

The complex includes several different buildings with various medical specializations. The scene was so dangerous and communications so weak, Mokhallalati said, that doctors holed up in one building had no idea what was going on in other parts of the compound.

“We are not moving around in the building,” he said. “It’s totally risky to move between buildings or look through the window as there are snipers and someone could shoot you.”

As far as he knew, he said, tanks remained at hospital entrances and Israeli forces were still inside, having managed to enter at least two buildings with “no resistance at all.” He said he had personally witnessed tanks at three gates to the hospital, and said he’d heard stories from colleagues about seeing people rounded up by Israeli troops.

In an earlier conversation, the doctor said he had never seen an armed fighter in the hospital. “I and my colleagues would not put our lives at risk because someone with a gun is around,” he said. “There are only civilians here.”

An Israeli military statement said troops “encountered explosives and terrorist squads” in the fight for entry into Shifa. Witness reports cited by Al Jazeera said Israeli soldiers had fanned out to search the compound.

By midday, there was no sign that any of the more than 240 Israeli hostages seized by Hamas and its allies on Oct. 7 had been found at the site, according to Israeli Army Radio, a military-run outlet. The report said at least five militants had been killed; there were no Israeli casualties. “No friction has been recorded so far between the troops and any of the patients or medical staff,” the report said.

Footage from the Reuters news agency showed thick smoke wafting through one section of the hospital as medical workers wheezed and coughed, some of them pulling scrubs and masks over their mouths as they moved through damaged hallways. The video also showed patients, including one who appeared to be a child, being wheeled on stretchers through clouds of smoke.

A video from the Health Ministry, published by Reuters, showed doctors inside the hospital saying that electricity had been cut off “completely,” making laboratory equipment inoperable and spoiling samples in the blood bank. One of the doctors, Shadi Issam Radi, said he had worked in the hospital’s intensive care unit for seven years, continuing even after his wife was killed in the war three weeks ago.

“I was obliged to bring the children with me, and I am still working,” Radi said in the video, his eyes sunken and his arms around his two young sons, who squirmed and looked frightened.

Zaqout, head of the ER, said in a statement that Israeli forces “blew up most of the hospital gates” before entering. He added that detentions were underway, with people “blindfolded and stripped of their clothes” before being led away.

With the collapse of communications systems and no access for journalists, there was no way for The Post to independently confirm conditions on the ground.

Since Friday, no ambulances have been allowed to reach al-Shifa Hospital, Health Ministry spokesman Ashraf al-Qudra said Tuesday. Some 700 patients were still present at the site, along with more than 400 health workers and about 3,000 displaced people who had sought refuge there, according to the latest United Nations figures.

Speaking on a choppy line from the complex early Wednesday, Qudra told The Post that only civilians were at the hospital and rejected claims to the contrary.

Israeli and U.S. intelligence assessments allege that Hamas operates a subterranean command center at the complex, using the injured and displaced as human shields.

Hamas has accused the IDF of targeting health facilities to cut off a lifeline for residents and to exact revenge for the group’s brutal assault, which killed more than 1,200 Israelis. The few medical and aid workers still left in northern Gaza have denied allegations that militants are using them for cover.

The battle around Shifa is the culmination of weeks of increasingly grave conditions at the compound and other Palestinian medical facilities, which have been overwhelmed by casualties and hampered by the lack of basic services. More than half of the hospitals in Gaza are no longer functional, according to the World Health Organization.

Fuel scarcity and damage to cellphone networks has led to a breakdown in communication that makes it impossible to accurately count the dead.

The Health Ministry stopped updating its tally on Friday at 11,078 but estimates that many more have died since then. There have been strikes on the Jabalya refugee camp in the north and in Khan Younis in the south since the counting stopped.

Human Rights Watch said Israel’s repeated attacks on medical facilities, personnel and transport “should be investigated as war crimes.” In a report Tuesday, the New York-based group said concerns about “disproportionate attacks are magnified for hospitals. Even the threat of an attack or minor damage can have massive life-or-death implications for patients and caregivers.”

Ishaq Sidr, the Palestinian minister of communications and information technology, said that the entire Gaza Strip could go incommunicado within the next 24 hours as a result of fuel shortages to power cell and internet lines.

“We are close to completely stopping the provision of all communications services unless the necessary fuel is secured,” he said. Another obstacle, Sidr added, is the lack of safety for workers to venture out and repair lines damaged in Israeli strikes of the past month.

Now, Sidr said, the ministry is scrambling for a Plan B, such as boosting networks from neighboring Egypt or pleading for help from Elon Musk’s Starlink satellite system. Without a fix soon, Sidr warned, the world won’t even be able to see the sliver of the war currently visible through a patchwork of social media posts and imperiled Palestinian journalists.

“Cutting off communications means cutting off all distress messages from Gaza,” he said. There will be “no coverage of all the destruction.”

Dadouch reported from Beirut, Allam from Cairo. Adela Suliman and Hajar Harb in London contributed to this report.