What Israel finds — or doesn’t — in the hospital could affect international sentiment about the invasion and influence the negotiations taking place on freeing more than 200 hostages being held by Hamas.

Eighteen hours after the raid on the hospital began, the Israeli military released photos and video that it said backed its assertions. It distributed images of 13 guns that it said its soldiers had discovered in the hospital, as well as a statement saying that it had found a military command center in the hospital’s M.R.I. unit.

In a video taken at the hospital, a military spokesman, Lt. Col. Jonathan Conricus, displayed caches of guns, ammunition, protective vests and Hamas military uniforms, some of which, he said, had been hidden behind M.R.I. machines and others in nearby storage units.

The New York Times was unable to verify the provenance of the weapons and equipment in the images or assess the claim of the command center’s existence. Apart from a gunfight outside the hospital at the start of the raid, there were no reports of clashes with Hamas gunmen at the site.

In a statement, Hamas dismissed the Israeli account as “a fabricated story that no one would believe.”

Should the Israelis in the end be unable to come up with compelling evidence that the hospital was used to house troops, store weapons and command fighters, they may find that the time left to achieve their stated goal — removing Hamas from power — has been curtailed. Israel’s targeting of Al-Shifa has already drawn global concern; a failure to prove the raid’s necessity could make Israel’s international partners less supportive of further Israeli operations in Gaza.

A spokesman for the U.S. National Security Council, John F. Kirby, rejecting Hamas claims that the United States had given the raid on Al-Shifa a “green light,” said Wednesday that Israel had not alerted the White House ahead of time.

The war began on Oct. 7, after Hamas led a terrorist attack on Israel, killing an estimated 1,200 people and kidnapping roughly 240 others, according to Israeli officials. In the 40 days since, Israel’s counterattack — by air, sea and land — has killed more than 11,000 people in Gaza, including more than 4,600 children, according to health officials in Gaza.

Israel is pushing to oust Hamas from power and re-establish control over a territory that it occupied between 1967 and 2005. Since 2007, when Hamas took full control of the narrow coastal enclave, Israel, in unison with Egypt, has maintained a tight blockade on Gaza.

Initially, at least, the raid on Wednesday seemed to pass without major bloodshed.

Israeli soldiers briefly exchanged fire with gunmen outside the hospital before entering, a senior military official said.

The hospital director, Mohammad Abu Salmiya, said in a broadcast interview with Al Jazeera that the soldiers had destroyed a wall of the hospital compound before entering, shattering several windows and wounding people inside with shrapnel.

“We can see the tanks before our eyes and we can see the soldiers walking inside the hospital,” he said.