JERUSALEM (JTA) — At least 15 people were killed and 200 injured when Israel shelled a U.N. school in northern Gaza serving as a shelter for displaced Palestinians.

The school in Beit Hanoun affiliated with the United Nations Relief and Works Agency was hit Thursday, the Ministry of Health in Gaza told international media outlets.

UNRWA spokesman in Israel Chris Gunness said on Twitter that there were multiple deaths and injuries in the attack.

Though 15 have been confirmed dead, Al Jazeera correspondent Nicole Johnston, who is in Gaza, said sources told her that up to 30 people had been killed.

Gunness also tweeted, “Precise co-ordinates of the UNRWA shelter in Beit Hanoun had been formally given to the Israeli army.”

The agency said it was the fourth time that a U.N. facility had been hit since the start of Israel’s Gaza operation on July 8.

According to the UNRWA, there are currently 140,469 displaced Palestinians in 83 agency shelters across Gaza.

The Palestinian Maan news agency reported that 37 Palestinians were killed across Gaza on Thursday morning, bringing the Palestinian death toll on the 17th day of Israel’s Operation Protective Edge to 734, with more than 4,000 injured.

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