The United Nations told French news agency Agence France-Presse (AFP) on Thursday that Israeli forces ordered people taking refuge in their shelter hit with deadly tank fire in southern Gaza's Khan Younis to leave by the following afternoon.
A spokeswoman for UNRWA, the agency for Palestinian refugees, confirmed testimony from displaced people in the shelter who said the army gave them until 5:00 pm (1500 GMT) on Friday to flee.
"The army called the UNRWA official through the loudspeaker, she went over to them next to the tanks, and they told her to notify us to vacate the premises by 5:00 pm tomorrow," Amal Lubbad told AFP, who is a displaced Gazan at the facility.
"We don't know where we'll go."
As fighting intensifies in Khan Younis, the Israeli military has taken to social media to publish evacuation orders covering swathes of the city where internet connectivity is limited.
"No specific evacuation request was communicated to UNRWA or those staying in its (the shelter's) vicinity," the military told the news agency.
Thirteen people were killed Wednesday when two tank shells struck the shelter, where thousands had taken refuge, UNRWA said.
"At least 13 people were killed and 56 injured, 21 of them critically, in what should have been a place of safety," Thomas White, the agency's Gaza director, said in a statement.
About 43,000 internally displaced people had been registered at the "massively overcrowded" shelter, White said.
"All of them now find themselves at the epicentre of the war in the Gaza Strip, with their lives in danger as the fighting is so close," he said.
The majority of Gaza's population- 1.7 million out of 2.4 million- have been forced from their homes with vast numbers cramming into UN shelters.
UNRWA chief Philippe Lazzarini said Wednesday's bombardment was a "blatant disregard of basic rules of war".
The compound had been clearly marked as a UN facility and its coordinates shared with Israeli authorities, he said on X, formerly Twitter.
Asked about the tank fire, the Israeli army said "a thorough review of the operations of the forces in the vicinity is underway", adding it was examining the possibility that the strike was a "result of Hamas fire".
The Israeli army is the only force known to have tanks operating in the Gaza Strip.
The United States also condemned the bombardment, with State Department spokesman Vedant Patel saying "civilians must be protected and the protected nature of UN facilities must be respected".