At least 16 people, including children, have been killed and more than 200 were injured in air strikes on a UN-run refugee shelter in Gaza.
Israel and Palestine have blamed each other for the incident with Israeli authorities initially claiming that a rocket fired by the Hamas could have missed the target and hit the UN school-turned-shelter.
Palestine has termed the Thursday attack as a brutal aggression of Israel.
Israel later said that it had responded to the rockets shot from the vicinity of the UN shelter, but had given four hours of time for the inmates to evacuate.
However, this claim was contested by United Nations Relief and Works Agency (UNRWA) spokesman Chris Gunness who said that the GPS coordinates of the school were shared with the country.
Gunness tweeted: "Precise co-ordinates of the UNRWA shelter in Beit Hanoun had been formally given to the Israeli army.
"Over the course of the day UNRWA tried to coordinate with the Israeli Army a window for civilians to leave and it was never granted."
The UNRWA, a humanitarian arm of the UN, is providing shelter to 140,000 Palestinians in 83 schools.
UN secretary-general Ban Ki-moon said in a statement that he was ‘appalled’ by the news and underscored the need to stop all fighting immediately.
"Many have been killed – including women and children, as well as UN staff.
"Today’s attack underscores the imperative for the killing to stop – and to stop now.
"I am telling to the parties – both the Israelis and Hamas and Palestinians – that it is morally wrong to kill your own people… Now it is time to sit down together, instead of killing each other," Ban Ki-moon said.
According to the UN Office for the Coordination of Humanitarian Affairs, 44% of the land in Palestine has been declared a ‘no-go zone’ by the Israeli army.
Israel has attacked at least three UN schools in the recent past, suspecting them to be housing Hamas militants.
At least 18 medical facilities, including five UNRWA health clinics, have been hit by airstrikes and shelling.
Image: Palestinian children weep at the funeral for their loved ones in Rafah, southern Gaza Strip, on 15 July. Photo courtesy of UNICEF / El Baba.