Gaza City, Gaza - Israeli forces said on Tuesday that they were carrying out an operation in Gaza's largest hospital, targeting a suspected Hamas command center located below thousands of ailing and sheltering civilians.

After warnings from the United States and others that the Al-Shifa hospital must be protected, the Israel Defense Forces (IDF) said in the early hours that they had entered the compound in Gaza City.

"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 in a statement.

"The... ground operation in Gaza [is] to defeat Hamas and rescue our hostages. Israel is at war with Hamas, not with the civilians in Gaza."

Joke of the Day Joke of the Night for November 18, 2024: The best jokes to laugh the day away

The United Nations estimates that at least 2,300 patients, staff, and displaced civilians are inside the facility, trapped by days of fierce fighting and aerial bombardments.

Witnesses have described conditions inside as horrific, with medical procedures taking place without anesthetic, families with scant food or water living in corridors, and the stench of decomposing corpses filling the air.

"There are bodies littered in the hospital complex and there is no longer electricity at the morgues," said hospital director Mohammad Abu Salmiya.

"We were forced to bury them in a mass grave," he added, estimating that 179 bodies had been interred so far, including seven newborns who died when their incubators lost power.

Before the assault, President Joe Biden urged Israel to take "less intrusive action relative to the hospital".

"The hospital must be protected," he said.

But Israel has repeatedly claimed that Hamas's military use of the facility "jeopardizes its protected status under international law," a claim that many international human rights lawyers refute.

Viral Video of the Day Viral Video of the Day for November 21, 2024: Toddler hilariously struggles with heavy gallon of milk!

Attempting to minimize any backlash against the operation, the IDF said it had given authorities in Hamas-run Gaza 12 hours' notice that military operations inside must cease.

"Unfortunately, it did not," an IDF statement read, again calling on "all Hamas terrorists present in the hospital to surrender."

Israel's military also stressed that its ground teams included medics and Arabic speakers "who have undergone specified training to prepare for this complex and sensitive environment."

The "intent" was that "no harm is caused to the civilians being used by Hamas as human shields," the Israeli military added.

Hamas denies deliberately locating paramilitary assets and personnel at hospitals, schools, and other civilian buildings.

Earlier on Tuesday, the White House said that US intelligence sources had corroborated Israel's claim that Hamas has buried an operational center under the hospital.

Hamas and another Palestinian militant group, Islamic Jihad, "operate a command and control node from Al-Shifa in Gaza City," National Security Council spokesman John Kirby told reporters.

"They have stored weapons there and they're prepared to respond to an Israeli military operation against that facility."