The Israel Defense Forces has carried out 37,000 airstrikes on Gaza and targetted more than 25,000 terrorist infrastructures and launch sites since Hamas' Oct. 7 attack, the IDF said Tuesday.

The IDF also acknowledged carrying out strikes on hospitals, schools and humanitarian shelters throughout the Gaza Strip, claiming to target "terrorists who are located and based in sensitive sites," the IDF said in a statement.

At least 23 people were killed and 73 others were injured after Israel struck a UNRWA school in a designated safe zone where displaced people are sheltering. Five UNRWA schools have been hit in the last 10 days, according to the UNRWA.

"UN facilities must be protected at all times. They must never be used for military or fighting purposes. No one is safe in Gaza, wherever they are. The people of #Gaza are children, women & men who have the right to live," the UNRWA said Tuesday.

In another strike on a safe zone in Mawasi Khan Yunis, at least 17 people were killed and 26 others were injured.

The Israel Defense Forces confirmed that it struck the school, alleging it struck terrorists who were operating in a UNRWA school.

-ABC News' Will Gretsky

Israel has carried out a strike on Nuseirat refugee camp, where internally displaced Palestinians have been told to shelter, for the second day in a row, according to Gaza Civil Defense.

This is the sixth school -- a designated safe zone -- to be targeted by Israeli Defense Forces' airstrikes in one week.

Israel has not confirmed whether Saturday's strike that killed 90 Palestinians killed two Hamas officials, including military chief Mohammed Deif, Israeli Prime Minister Benjamin Netanyahu said in a press conference.

"There is still no absolute certainty that the two have been eliminated, but I want to assure you that one way or another we will reach the entire top of Hamas," Netanyahu said.

Netanyahu said he was briefed about the type of weapons that would be used and the expected "collateral damage," as well as confirming Israel did not believe any hostages were held in the area, before giving the go ahead for the strike.

"Why should we risk something leaking out? Suppose something leaked, Deif and his deputy would go underground in a second. We update our American friends when necessary," Netanyahu said.

Asked about not telling the U.S. about the strike beforehand, Netanyahu said it was to avoid an information leak.

-ABC News' Anna Burd