UNITED NATIONS (Reuters) - Israel fired on seven United Nations schools during the 2014 Gaza war, killing 44 Palestinians who had sought shelter at some sites, while Palestinian militants hid weapons and launched attacks from several empty U.N. schools, a U.N. inquiry found.

United Nations Secretary General Ban Ki-moon listens during a news conference with Salim al-Jabouri, speaker of the Iraqi Council of Representatives, in Baghdad March 30, 2015. REUTERS/Karim Kadim/Pool

“I deplore the fact that at least 44 Palestinians were killed as a result of Israeli actions and at least 227 injured at United Nations premises being used as emergency shelters,” U.N. Secretary-General Ban Ki-moon wrote in a letter on Monday accompanying a summary of the inquiry’s findings.

“I am dismayed that Palestinian militant groups would put United Nations schools at risk by using them to hide their arms,” Ban wrote, adding that in two cases, the militants had probably fired from the schools.

The U.N. Security Council is due to discuss the report on Tuesday, diplomats said.

More than 2,100 Palestinians, mostly civilians, were killed during the Gaza conflict last July and August. Sixty-seven Israeli soldiers and six civilians in Israel were killed by rockets and attacks by Hamas and other militant groups.

Israel and Hamas, the Islamist group that dominates Gaza, said they would cooperate with the inquiry, launched by Ban in October and headed by retired Dutch General Patrick Cammaert.

Israel’s Foreign Ministry spokesman Emmanuel Nahshon said in a statement that all the incidents in the report attributed to Israel had been “subject to thorough examinations and criminal investigations have been launched where relevant.”

“Israel makes every effort to avoid harm to sensitive sites, in the face of terrorist groups who are committed not only to targeting Israeli civilians but also to using Palestinian civilians and U.N. facilities as shields,” Nahshon said.

Hamas spokesman Sami Abu Zuhri told Reuters that the group would thoroughly study the report and had no information about weapons being hidden in U.N. schools.

The U.N. inquiry found that six of the seven schools hit by Israel were designated emergency shelters. The three schools used by Palestinian militants to hide weapons, and in some cases, launch attacks, were not being used as emergency shelters.

“All coordinates of United Nations installations were available to (Israeli) units on the ground and were clearly and visibly marked on maps. The board noted, though, that, in spite of such measures, (U.N.) facilities were hit,” the report said.

The International Criminal Court launched an inquiry in January into possible war crimes committed during the Gaza conflict in 2014.