New York: The Secretary-General of the United Nations, Antonio Guterres, on Saturday voiced his anguish over the suspected air strike on a convoy of ambulances outside Al-Shifa Hospital in Gaza.

The attack on Friday left many dead and injured, according to reports.

While condoling the loss of lives in the attack outside the Gaza hospital, the UN chief also called for the immediate release of hostages by terror group Hamas.

"I do not forget the terror attacks committed in Israel by Hamas and the killing, maiming and abductions, including of women and children. All hostages held in Gaza must be released immediately and unconditionally," Guterres said.

However, opening up on the suspected air strike on the ambulance convoy outside the Gaza hospital, the UN Secretary-General said, "I am horrified by the reported attack in Gaza on an ambulance convoy outside Al Shifa hospital. The images of bodies strewn on the street outside the hospital are harrowing."

Underlining the dire humanitarian crisis in Gaza, with reports of food, water, medicine, and fuel for hospitals and water plants in short supply, Guterres added, "Not nearly enough food, water and medicine are coming in to meet people's needs. Fuel to power hospitals and water plants is running out."

He claimed that the morgues were overflowing with bodies in Gaza and the shops were empty. He also pointed to the 'abysmal' situation with regard to sanitation, adding that there were fears of children coming down with ailments.

"Morgues are overflowing. Shops are empty. The sanitation situation is abysmal. We are seeing an increase in diseases and respiratory illnesses, especially among children. An entire population is traumatized. Nowhere is safe," he added.

Responding to Guterres's statement, Israel's Ambassador to the United Nations, Gilad Erdan, took a swipe at the UN Secretary-General for rushing to condemn Israel without seeking a full understanding of the situation.

Invoking the UN chief's remarks in light of a previous suspected air strike at Gaza's al-Ahli hospital, he accused Guterres of making false claims about aid not entering Gaza and ignoring the alleged misuse of ambulances by Hamas to further its nefarious actions.

Following the attack on the al-Ahli hospital, the UN chief posted from his social media handle, "I am horrified by the killing of hundreds of Palestinian civilians in a strike on a hospital in Gaza today, which I strongly condemn."

Israel's permanent envoy to the UN said Guterres chose to unjustly condemn Israel while neglecting the issue of hostages.

"@antonioguterres once again, you rush to condemn Israel without even bothering to ask what happened (eg. al-Ahli hospital), you blatantly lie regarding the lack of aid entering Gaza, and you completely ignore the fact that Hamas intentionally exploits ambulances for terror. You didn't ask for the truth, bc you don't care about the truth. Instead, you prefer to falsely condemn Israel, while making our hostages a literal footnote. It's absolutely disgraceful. Where was your 'horror' when Hamas deliberately targeted Israeli ambulances with RPGs and executed paramedics in cold blood?" Erdan added.

Earlier, Israeli airstrikes damaged a building near the emergency entrance of Al-Quds Hospital in Gaza City, injuring 21 people, the Palestine Red Crescent Society (PRCS) said in a post on social media.

"This has resulted in significant damage to the location and the injury of 21 displaced individuals," the aid group said.

A UN-run school serving as a shelter in a refugee camp in the northern Gaza Strip was also struck, resulting in 15 fatalities and more than 70 injuries, according to the Hamas-controlled Ministry of Health in Gaza.

Meanwhile, US Secretary of State Antony Blinken conveyed his condolences to the kin of more than 70 UN staffers, who have lost their lives in the ongoing conflict in Gaza, CNN reported.