Hamas and Gaza health officials deny militants operate in Shifa — a hospital that employs some 1,500 people and has more than 500 beds, according to the Palestinian news agency. Palestinians and rights groups say Israel has recklessly endangered civilians as it seeks to eradicate Hamas.

As Israel tightens its hold on northern Gaza, leaders have talked of expanding the ground operation into the south to root out Hamas. Most of Gaza’s 2.3 million people have already crowded into the territory’s south, where a worsening fuel shortage threatens to paralyze the delivery of humanitarian services and shut down mobile phone and internet service.

The war between Israel and Hamas erupted after the militant group killed some 1,200 people and seized around 240 captives in an Oct. 7 attack that shattered Israelis’ sense of security.

Israeli airstrikes have since killed more than 11,200 people, two-thirds of them women and minors, according to the Palestinian Health Ministry in Ramallah, which coordinates with the ministry branch in Hamas-ruled Gaza. Another 2,700 have been reported missing, with most believed to be buried under the rubble. The ministry’s count does not differentiate between civilian and militant deaths.

Israeli forces launched their raid into the large Shifa compound around 2 a.m. and remained on the grounds after nightfall Wednesday, with tanks stationed outside and snipers on nearby buildings, Munir al-Boursh, a senior official with Gaza’s Health Ministry inside the hospital, told The Associated Press. It was not possible to independently assess the situation inside.

Al-Boursh said that for hours, the troops ransacked the basement and other buildings, including those housing the emergency and surgery departments, and searched the grounds for tunnels. Troops questioned and face-screened patients, staff and people sheltering in the facility, he said, adding that he did not know if any were detained.

“Patients, women and children are terrified,” he told the AP by phone.

Neither the Palestinians nor the military reported any clashes inside the hospital. The military said its troops killed four militants outside the hospital at the start of the operation. Throughout days of fighting in the surrounding streets in previous days, there were no reports of militants firing from inside Shifa.

The Israeli military said it was carrying out a “precise and targeted operation against Hamas in a specified area in the hospital,” and that its soldiers were accompanied by medical teams bringing in incubators and other supplies.

It added that forces were also searching for hostages. The plight of the captives, who include men, women and children, has galvanized Israeli support for the war. Families and supporters of the hostages are holding a protest march from Tel Aviv to Jerusalem.

The video released by the military from inside Shifa showed three duffel bags it said it found hidden around an MRI lab, each containing an assault rifle, grenades and Hamas uniforms, as well as a closet that contained a number of assault rifles without ammunition clips. A laptop was also discovered and taken for study. The AP could not independently verify the Israeli claims that the weapons were found inside the hospital.

“These weapons have absolutely no business being inside a hospital,” Lt. Col. Jonathan Conricus, a military spokesman, said in the video, adding that he believed the material was “just the top of the iceberg.” The military said the search was continuing, but it did not immediately show any sign of tunnels or an extensive military center.