The Palestinian Red Crescent Society has condemned the targeting of a convoy of ambulances in Gaza by Israeli forces on Friday, which it says killed 15 people and wounded more than 60 others.

The PRCS said in a statement early Saturday that one of its ambulances was struck "by a missile fired by the Israeli forces", about two meters from the entrance to the Al-Shifa hospital in Gaza City.

The attack resulted in the deaths of 15 civilians and wounded 60 other people, the PRCS said, mirroring figures released earlier by the Hamas-run health ministry.

Another ambulance, belonging to the health ministry, was "directly targeted" by a missile around one kilometre from the hospital, causing injuries and damage, it said.

The PRCS, part of the International Red Cross and Red Crescent Movement, added that deliberately targeting medical teams constituted "a grave violation of the Geneva Conventions, a war crime".

Israel's military said it had launched an air strike on "an ambulance that was identified by forces as being used by a Hamas terrorist cell in close proximity to their position in the battle zone".

"A number of Hamas terrorist operatives were killed in the strike," a military statement said.

An AFP journalist at the scene of the attack saw multiple bodies beside the damaged ambulance outside the hospital, which is overcrowded with civilians seeking shelter from Israeli bombing as well as those wounded.

In the aftermath of the strike, they saw a child being carried away and a dead horse tied to a cart beside a blood-spattered Palestinian Red Crescent ambulance.

The Hamas government said Israeli forces hit "a convoy of ambulances which was transporting the wounded" from Gaza City towards Rafah in the south of the territory.

World Health Organization chief Tedros Adhanom Ghebreyesus said he was "utterly shocked by reports of attacks on ambulances evacuating patients close to Al-Shifa hospital in Gaza, leading to deaths, injuries and damage".

"We reiterate: patients, health workers, facilities and ambulances must be protected at all times. Always," he wrote on X, formerly Twitter.

Lynn Hastings, the United Nations humanitarian coordinator for the Palestinian territories, expressed "alarm" over the strike "as patients were being evacuated to find safety".

Al-Shifa hospital has a bed occupancy rate of 164 percent according to the WHO, which on Wednesday warned a shortage of fuel for generators "immediately risks the lives" of patients.

Some 16 hospitals across Gaza are no longer functioning because of damage from strikes and the lack of fuel, according to the Hamas-run health ministry.

More than 23,500 people have been wounded across Gaza in four weeks of war, the health ministry said, while the death toll has surpassed 9,200.

Israel began its ferocious aerial bombardment of the Gaza Strip after Hamas militants launched a cross-border attack on October 7 which killed more than 1,400 people, mainly civilians, according to Israeli authorities. More than 240 hostages were also seized during the attack.