GAZA STRIP, Palestinian Territories, June 7, 2024 (BSS/AFP) - The head of the UN Palestinian refugee agency said Thursday that Israel had bombed one of its schools in Gaza "without prior warning" to thousands of displaced people sheltering there.

"Another UNRWA school turned shelter attacked," Philippe Lazzarini wrote on social media platform X, of the school in the Nuseirat area of central Gaza.

Israeli military spokesman Rear Admiral Daniel Hagari said nine "terrorists" were killed when fighter jets hit the school.

Hagari said in a televised address that the jets had attacked three classrooms where about 30 from Islamic Jihad and Hamas were hiding.

The Al-Aqsa Martyrs hospital said at least 37 people were killed in the strike.

Lazzarini said the school was sheltering 6,000 displaced people when it was hit.

He added that UNRWA "shares the coordinates of all its facilities (including this school) with the Israeli army and other parties in the conflict".

"Attacking, targeting or using UN buildings for military purposes are a blatant disregard of International Humanitarian law," Lazzarini said.

Israeli rights group B'Tselem called the strike a "suspected war crime".

"If, as Israel claims, Hamas used the school to plan military operations, this action is illegal, but it cannot justify the massive harm to civilians who sought shelter in the school from the horror of prolonged fighting," the group said in a statement.

"As demonstrated throughout the war, the killing of civilians is an unavoidable result of the character of Israel's military activity in the Gaza Strip," it said, urging the international community to help stop the fighting.

In a separate incident, Hagari said Israeli troops killed three Hamas  who were trying to enter the country from the Rafah area by breaching the border fence.