Israeli troops have entered Al Shifa hospital in Gaza City but say there has been no fighting and no friction with civilians, patients or staff.
Israel says its forces are operating in and around Gaza's biggest hospital, a chief objective in its campaign to destroy Palestinian Hamas militants the army says stored weapons and ran a command centre in tunnels beneath the buildings.
Israeli troops forced their way into Al Shifa hospital in the early hours of Wednesday and spent the day deepening their search.
An army video showed automatic weapons, grenades, ammunition and flak jackets it said were recovered from an undisclosed building within the complex.
"The troops continue to search the hospital in a precise, intelligence-based, manner," army spokesperson Rear Admiral Daniel Hagari told reporters.
"We will continue to do so in order to gather further information, to discover additional assets and to expose the terror activities within the hospital."
The military made no mention on Wednesday of finding any tunnel entrances in Al Shifa.
It previously said Hamas had built a network of tunnels under the hospital.
Hamas has denied it and dismissed the latest army statements.
"The occupation forces are still lying ... as they brought some weapons, clothes and tools and placed them in the hospital in a scandalous manner," Qatar-based Hamas senior member Ezzat El Rashq said.
Hamas denies there was a military command post under Al Shifa hospital.
"We have repeatedly called for a committee from the United Nations, the World Health Organization and the Red Cross to verify the lies of the occupation."
Israeli forces raided the Shifa complex on Wednesday evening "for the second time in 24 hours" WAFA, the official Palestinian news agency, reported.
Bulldozers and military vehicles were used, the agency said, citing local sources.
Hamas-affiliated Shehab news agency reported early on Thursday that Israeli tanks raided Al Shifa from the complex's southern side and gunfire was heard.
Israel began its campaign against the Islamist group that rules Gaza after militants rampaged through southern Israel on October 7.
Israel says 1200 people were killed and 240 taken hostage.
Since, Israel has put Gaza's population of 2.3 million under siege and carried out an aerial bombardment.
Gaza health officials say about 11,500 Palestinians are confirmed killed, around 40 per cent of them children, and more are buried under the rubble.
Israel has ordered the entire northern half of Gaza evacuated and around two-thirds of residents are homeless.
Israeli says weapons were found in a medical closet at Al Shifa hospital.
The first truck carrying fuel into Gaza since the start of the war crossed from Egypt on Wednesday to deliver diesel to the United Nations, though it will do little to alleviate shortages that have hampered relief operations.
The delivery was made possible by Israel approving 24,000 litres of diesel to be allowed into Gaza for UN aid distribution trucks, though not for use at hospitals, according to a humanitarian source.
The UN Security Council on Wednesday called for urgent and extended humanitarian pauses in fighting for a "sufficient number of days" to allow aid access.
It also called in a resolution for the immediate and unconditional release of all hostages held by Hamas.
The 15-member council overcame an impasse in four attempts to take action last month.
Israel has so far rejected calls for a ceasefire. A pause has been discussed, however, in negotiations mediated by Qatar to release some hostages taken in the October 7 attack.