At least 15 people were killed Thursday when a compound housing a United Nations school in Gaza was struck while Palestinians seeking shelter from street clashes were inside.

The Associated Press reported that Israeli tank shells hit the compound; the Israeli military said it was investigating the incident and that rockets launched by Hamas had also landed in the area during the clashes.

IDF Capt. Eytan Buchman told the Times of Israel there was “serious combat in the area.”

“We can also confirm that terror rockets from the area were fired and landed in the neighborhood of the facility this afternoon,” Buchman said. “We are carefully reviewing the matter.”

Palestinian medics treat a child wounded in an Israeli strike on a compound housing a U.N. school in Beit Hanoun, in the northern Gaza Strip, at the emergency room of the Kamal Adwan hospital in Beit Lahiya, Thursday, July 24, 2014. (AP Photo/Lefteris Pitarakis)

Palestinian medics treat a child wounded in a strike on a compound housing a U.N. school in the Gaza Strip, Thursday, July 24, 2014. (AP Photo/Lefteris Pitarakis)

Without concluding whose munition hit the facility, the IDF later on Thursday wrote on Twitter that Hamas was firing rockets in the area toward Israel and that some had fallen short in the neighborhood where the facility was located.

“In recent days, Hamas has fired rockets from an area of Beit Hanoun where an UNRWA shelter is located,” the IDF said.

“Last night, we told Red Cross to evacuate civilians from UNRWA’s shelter in Beit Hanoun between 10 a.m. and 2 p.m. UNRWA and [the] Red Cross got the message,” the IDF said in a series of tweets.

“Hamas prevented civilians from evacuating the area during the window that we gave them,” the IDF added.

“Today Hamas continued firing from Beit Hanoun. The IDF responded by targeting the source of the fire,” the Israeli military said. “Also today, several rockets launched from Gaza toward Israel fell short and hit Beit Hanoun.”

A U.N. spokesman tweeted that there were reports of Hamas rockets having  hit the neighborhood of Beit Hanoun.

“Civilians yet again caught between two sides paying an unimaginable price,” UNRWA spokesman Chris Gunness tweeted.

Israel has said it is doing its utmost to protect Palestinian civilians during its operation to stop the barrage of rockets being launched into the country, but says Hamas is launching and storing its weapons in civilian areas, including schools, mosques and hospitals.

The Israel Defense Forces released a photo Wednesday it said showed the entrance to a Hamas tunnel situated between a school and a mosque. Hamas uses its tunnels to infiltrate the border and carry out attacks on Israelis.

The United Nations Relief and Works Agency, which runs the facility that was struck Thursday, revealed this week for a second time that rockets were being stored by militants in one of its schools.

The agency said the school in which the rockets were found was situated between two other UNRWA schools that are currently housing 3,000 Palestinians who fled their homes.

It’s unclear whether the facility hit Thursday was where rockets had been hidden or nearby.