A top health official in Gaza said all 31 premature babies at Al Shifa hospital had been evacuated from the facility which the WHO has described as a "death zone".
The move was confirmed by the Palestinian Red Crescent Society (PCRS), which said its teams carried out the evacuation in coordination with UN agencies including the World Health Organization.
Mohammed Zaqut, director general of hospitals in Gaza, told AFP news agency "all 31 premature babies in Al Shifa hospital... have been evacuated" along with three doctors and two nurses.
"Preparations are under way" for them to enter Egypt, he added.
An AFP journalist at the scene saw crowds of sick, injured and displaced people walking towards the seafront, with the health ministry saying 120 patients had stayed behind, among them a number of premature babies.
"Many patients can not leave the hospital as they are in the ICU beds or the baby incubators," Ahmed al Mokhallalati, a doctor at the hospital, wrote Saturday on X, formerly Twitter.
The area in and around Al Shifa has been battered by multiple Israeli attacks for weeks.
Israeli forces conducted a raid on Al Shifa Hospital last week in Gaza, where thousands of Palestinians sought shelter, following days of intense Israeli air attacks on the hospital and its surrounding area.
The Israeli military stated it was an "operation against Hamas in a specified area" at Al Shifa, describing it as a "targeted operation" on Gaza's largest medical facility.
Hamas rejects the claim. Israel has not produced evidence to back up its assertion.
On Saturday, the Israeli army had given all those inside the Al Shifa Medical Complex a one-hour deadline, forcing even patients in critical need of medical care to leave the healthcare facility.
The Gaza media office said in a statement: “More than 500 patients and wounded, exhausted by hunger, thirst, and pain, were forced by the Israeli army to leave the Al Shifa medical complex, to meet their fate in the streets, while they are in dire need of extensive health and medical care, especially since the majority of them are in serious conditions".
The health ministry in Gaza says Israel's brutal military offensive has killed more than 12,300 Palestinians, mostly civilians including thousands of women and children.
The PCRS confirmed its teams had "successfully evacuated... 31 premature babies from Al Shifa" in a statement that said they were "transported by PRCS ambulances to the south".
In an overnight announcement, the WHO said it had sent an assessment team to the hospital and described it as a "death zone", saying it was "urgently developing plans for the immediate evacuation of the remaining patients, staff and their families".
The visit came after hundreds fled the hospital, Gaza's largest, following what Al Shifa's director said were Israeli army orders for it to be emptied.
Since November 11, when fuel supplies ran out at Al Shifa, eight babies have died due to the lack of electricity to run incubator units , the health ministry has said.