Heavy fighting between Israeli forces and Palestinian resisrtance has raged near Gaza's biggest hospital, Al-Shifa, an AFP correspondent at the scene said, stretching the area's already crippled health system.

The government in Gaza and the hospital's director said an Israeli strike on the key health facility on Friday killed 13 people. 

"We call on all international and Arab parties to immediately intervene to stop the targeting of hospitals in Gaza," said a spokesman for the Gaza health ministry, Ahsraf Al-Qudra.

Aid agency Doctors Without Borders said it was "extremely concerned" about the safety of patients and medical staff at Al-Shifa Hospital.

"Over the last few hours, the attacks against Al-Shifa Hospital have dramatically intensified," it said in a statement posted online on Saturday morning.

"Our staff at the hospital have reported a catastrophic situation inside just a few hours ago."

Maher Sharif, a nurse heading to the Al-Shifa hospital when it was struck on Friday, described how people threw themselves to the ground.

"I saw dead bodies, including women and children," she said, according to a statement by Doctors Without Borders.

"The scene was horrific."

Gaza resident Hanane told AFP his daughter was being treated at Al-Shifa after being wounded as she queued outside a bakery. She "starts shaking" with each explosion, he said.

'Babies Killed'

French President Emmanuel Macron told the BBC that civilians were dying as a result of Israel's air and expanding ground campaign. 

"These babies, these ladies, these old people are bombed and killed," the French leader said, in his first acknowledgement of Israeli killings of Palestinians. "So there is no reason for that and no legitimacy. So we do urge Israel to stop," he added.

However, he maintained that Israel had the right to defend itself, after Hamas operation Al-Aqsa Flood on Gaza envelope on October 7.

The Gaza health ministry says Israeli fighting has killed more than 11,000 people, mostly children and women.

US Secretary of State Antony Blinken also expressed concern over the death toll. "Far too many Palestinians have been killed," he said during a visit to New Delhi on Friday.

Blinken repeated, however, his support for Israel and welcomed "progress" after the country formally agreed to four-hour pauses in its campaign in parts of Gaza where tens of thousands have fled in search of safety.

"I was also very clear that much more needs to be done in terms of protecting civilians and getting humanitarian assistance to them," Blinken said.

'On its knees'

Palestinians reported strikes or sniper fire at two hospitals and a school in Gaza on Friday.

The bodies of 50 people killed in a strike on Gaza City's Al-Buraq school were taken to the Al-Shifa hospital, its director said. 

Fighting has reduced some streets in the city to ruins, AFP correspondents there said, describing the sound of heavy gunfire, explosions and the buzz of Israeli military drones as night fell.

After five weeks of Israel's brutal war, the Gazan health system was "on its knees", the head of the World Health Organization, Tedros Adhanom Ghebreyesus, told the UN Security Council.

A child is killed on average every 10 minutes in the Gaza Strip, Ghebreyesus told the United Nations Security Council on Friday.

He said that half of Gaza's 36 hospitals and two-thirds of its primary healthcare centers were not functioning and those that were operating were way beyond their capacities, describing the healthcare system as being "on its knees."

The International Committee of the Red Cross echied his comments: "Overstretched, running on thin supplies and increasingly unsafe, the healthcare system in Gaza has reached a point of no return."

War expansion risk

Tens of thousands of people have fled to the south of the territory in recent days, often on foot and taking only the things they could carry.

Almost 1.6 million people have been internally displaced since October 7, the UN agency for Palestinian refugees (UNRWA) said -- nearly two thirds of Gaza's population.

But the UN estimates tens of thousands of civilians remain in the fiercest battle zones in the north.

The conflict has also stoked regional tensions, with cross-border exchanges between the Israeli army and Lebanon's Hezbollah.

Yemen's Huthi rebels say they have launched "ballistic missiles" at southern Israel.

Iran's Foreign Minister Hossein Amir-Abdollahian said the expansion of the Israeli war on Gaza had become "inevitable".

Saudi Arabia is hosting Arab leaders and Iran's president for a summit this weekend in emergency meetings of the Arab League and the Organisation of Islamic Cooperation, in an ultimate attempt to stop the Israeli war.