A day after it took control of the Gaza Strip’s largest hospital, the Israeli military on Thursday afternoon was still searching the site that Israel has said concealed a secret Hamas base, and to bolster its case offered video of more weapons it said it had found there and what it described as a tunnel entrance.
The images presented by Israel from the hospital, Al-Shifa, in Gaza City, could not be independently verified, and still have not proven the existence of the sprawling Hamas operation that it said the hospital concealed.
But Israeli officials said the search was bound to be slow, citing the physical difficulties and the risks. They added that Hamas had plenty of warning that Israeli forces were coming and time to remove evidence. In an apparent attempt to rebuff skepticism of the evidence released thus far, Rear Adm. Daniel Hagari, the chief spokesman for the Israeli military, said Thursday evening at a news briefing that troops were searching the hospitals, building by building, sometimes while under fire.
“This is a complex activity that needs time in order to most importantly ensure our forces’ security, and then operational success,” he said. “In Shifa, Rantisi, Al-Quds and other hospitals, we are finding Hamas activity aboveground and underneath it. This is no coincidence — this is Hamas’s method.”
Since invading Gaza 20 days ago, Israel has presented Al-Shifa as one of its primary targets, saying it sits atop a network of subterranean fortifications installed by Hamas, the armed Palestinian group that controlled the entire territory until the invasion began. Hamas and the hospital leadership have denied the accusations.
The claim that Hamas operated from within the sprawling hospital complex has been central to Israel’s defense of the death toll caused by its military campaign in Gaza, which has killed more than 11,000 people, according to Gazan health officials. Israeli officials say that the extreme loss of life has been caused in part by Hamas’s decision to hide its military fortifications and command centers inside civilian infrastructure like Al-Shifa.
One of the videos released on Thursday by the Israeli military showed a white pickup truck on the hospital grounds and, laid out on the ground near it, the arsenal the narrator said had been its contents: automatic rifles, rocket-propelled grenades, ammunition magazines, hand grenades and other gear.
Another video shows excavated earth and a doorway into an underground passage, which The New York Times has confirmed is at the northern perimeter of the sprawling hospital complex. Israeli forces appear to have destroyed a small structure and dug up an extensive area to uncover the opening, an analysis of satellite imagery and video shows.
On Wednesday, the military released video showing about a dozen guns, a grenade, protective vests and military uniforms that it said soldiers had found within an M.R.I. unit at the hospital.
At a news conference in Beirut, Lebanon, on Thursday, Osama Hamdan, a Hamas spokesman, called that video “a weak and ridiculous narration.” Mr. Hamdan accused Israel of planting the weaponry to show a militant presence at the hospital.
Israel’s ability to prove its claim could determine whether its foreign allies continue to support its military response to Hamas’s Oct. 7 attack on Israel. White House officials have said they believe, based on intelligence gathered independently of Israeli sources, that Hamas used the hospital as a base.
Israel received broad international support after the Hamas-led raid killed roughly 1,200 people, most of them civilians, according to Israeli officials. But as the Israeli counterattack has dragged on, devastating much of Gaza, there have been signs that allies were beginning to take a more nuanced position.
The United Nations Security Council called on Wednesday for immediate, dayslong pauses in the fighting to allow more aid to reach civilians. The United States — a key ally that often vetoes U.N. statements critical of Israel — abstained from voting on the resolution, allowing it to pass.
“The occupation resorted to this farce to cover up the fall of its alleged story,” he added.
He said Israeli troops had “terrorized the patients and detained them in a barbaric manner,” and accused them of “destroying the medicine warehouse and disabling the M.R.I. machine.”
On Oct. 27, the day that its forces invaded Gaza, the Israeli military published a map of the site that suggested Hamas was operating four underground complexes beneath the hospital’s internal medicine department, its chest and dialysis department, its M.R.I. department and a rest area at its western edge. The map also suggested that Hamas ran a command center at or near the hospital’s outpatient clinic.
The army has not yet presented evidence publicly that any of those five sites exist. It did say in a statement that soldiers had found an aboveground command center in the M.R.I. unit, without providing further evidence. Hamas dismissed the assertion as “a fabricated story that no one would believe.”
A spokesman for the Israeli military, Maj. Nir Dinar, said that Israel needed more time to find and present evidence.
“It takes time because Hamas knew we were coming, and they’ve tried to hide evidence of their war crimes,” Major Dinar said. “They’ve messed up the scene, they’ve brought in sand to cover some of the floors, and they’ve created double walls.”
Hwaida Saad, Aric Toler and Malachy Browne contributed reporting.