Israeli soldiers entered part of Shifa Hospital in the early hours of Wednesday and began fighting Hamas there, the Israel Defence Forces announced.
"Based on intelligence information and an operational necessity, IDF forces are carrying out a precise and targeted operation against Hamas in a specified area in the Shifa Hospital," the military said.
The military added that forces were joined by medical teams and Arabic speakers 'who have undergone specified training to prepare for this complex and sensitive environment, with the intent that no harm is caused to the civilians being used by Hamas as human shields'.
Briefing reporters on Tuesday night, IDF spokesperson Rear Admiral Daniel Hagari warned that Gaza's medical facilities were losing their protected status because of Hamas activities there.
"In recent weeks we have stressed again and again, that because of Hamas's use of hospitals for military purposes, it will lose its special protection under intentional law," Rear Admiral Hagari said.
"We are forced to operate in a focused and careful manner against Hamas's terror infrastructure in the hospitals," he said.
"We call on the Hamas operatives who are hiding in the hospitals to surrender so as not to endanger those in the hospitals."
The White House confirmed Israel's assessment on Tuesday.
"We have information that Hamas and the Palestinian Islamic Jihad use some hospitals in the Gaza Strip, including Al Shifa, and tunnels underneath them to conceal and to support their military operations and to hold hostages," White House National Security Council spokesperson John Kirby told reporters.
Citing American findings, Kirby added, "Hamas and the Palestinian Islamic Jihad members operate a command and control [center] from Al Shifa in Gaza City. They have stored weapons there and they're prepared to respond to an Israeli military operation against that facility."
As reported by the Tazpit Press Service, Hamas makes extensive use of the Shifa Hospital.
Located in Gaza's North Rimal neighborhood and boasting 570 beds, Shifa is the Strip's largest medical center, serving the medical needs of hundreds of thousands of Palestinians. It was originally built by British authorities in 1946. In the 1980s, Israel renovated and expanded Shifa as part of an initiative to improve Gaza living conditions.
As far back as 2009, the Israeli Security Agency (Shin Bet) reported during the Gaza war of that year that Hamas operatives were hiding in the hospital, and that the basement had become Hamas's headquarters.
In addition to being used to hide Hamas leaders and hostages, the terror group is known to have launched rockets, tortured suspected collaborators and hoarded a half-million liters of fuel in the hospital compound.