The United Nations on Tuesday dismissed as "ridiculous" an assertion by Israel that there was enough food in the Gaza Strip to last for a long period of time, despite the closure of all 25 bakeries in the enclave supported by the World Food Programme.

The aid workers and their ambulances were found Monday in a hastily dug grave, which was apparently plowed over by bulldozers, the UN said.

The United Nations has said it will “reduce its footprint” in the Gaza Strip after an Israeli tank strike hit one of its compounds last week, killing one staffer and wounding five others.

DEIR AL BALAH, Gaza Strip (AP) — An Israeli airstrike on Thursday killed at least 27 Palestinians sheltering at a school in northern Gaza and wounded 70 more, said Health Ministry spokesman Zaher al-Wahidi, as Israeli forces have expanded their strikes and evacuation orders across the war-torn territory in recent days.

New military corridors, airstrikes, evacuation and a blockade of humanitarian aid exacerbate the humanitarian situation in Gaza. On Wednesday, Israel's prime minister, Benjamin Netanyahu, said that Israeli forces were establishing a new security corridor between the cities of Rafah and Khan Younis in the southern Gaza Strip.

The offensive comes as Israel faces criticism after the United Nations said bodies of aid workers were found in a “mass grave."

Israeli Defense Minister Israel Katz announced Wednesday a major expansion of the military’s operation in Gaza involving the seizure of large areas of land that would be “incorporated into Israel’s security zones.

Israel unilaterally blocked the aid corridor from Egypt at the start of March, and resumed its full scale bombing of Gaza on March 18, breaking a ceasefire with Hamas