Three Israeli soldiers were killed Wednesday when explosives rigged inside a tunnel hidden under a United Nations health clinic in Gaza detonated, comprising yet another example of the exploitation of internationally-protected facilities by Palestinian terror groups.

The Times of Israel reported:

An Israeli elite squad searching for tunnels near Khan Younis uncovers a booby-trapped opening in a small UNRWA health clinic.

The troops send in sniffing dogs and a small robot to minimize damage to the structure, but despite the precautionary measures, the explosives rigged to the tunnel are detonated, demolishing the building on top of the soldiers.

Wednesday’s incident follows an admission for the third time by UNRWA – the U.N.’s main agency in Gaza – that it found another stash of rockets in one of its schools.

UNRWA spokesman Chris Gunness said in a statement, “We condemn the group or groups who endangered civilians by placing these munitions in our school. This is yet another flagrant violation of the neutrality of our premises. We call on all the warring parties to respect the inviolability of U.N. property.”

U.N. Secretary-General Ban Ki-moon last week expressed alarm that 20 rockets being stored in one of the schools had gone missing.

“By doing so, those responsible are turning schools into potential military targets, and endangering the lives of innocent children, U.N. employees working in such facilities and anyone using the U.N. schools as shelter,” Ban said in a statement.

Reuters quoted Gunness who said that the organization was calling in a U.N. munitions expert to dispose of the rockets, but that the expert could not get to the premises due to the ongoing fighting.

The IDF said it was reviewing an incident Tuesday night during which explosives hit a U.N. school, killing 15. The IDF said its soldiers were being shot at by Palestinian militants firing mortars from the area of the school.

“In response, soldiers fired toward the origins of fire. And we’re still reviewing the incident,” the IDF said, according to the Associated Press.

UNRWA blamed Israel for the attack. “I condemn in the strongest possible terms this serious violation of international law by Israeli forces,” UNRWA commissioner-general Pierre Krahenbuhl said in a statement.

The White House also condemned the shelling but notably did not assign blame in its statement for the incident to either Israel or Hamas.

White House spokeswoman Bernadette Meehan said the U.S. was “extremely concerned” that thousands of Palestinians are unsafe in U.N. shelters.

Even though Meehan did not say Israel was responsible, this is how the Associated Press tweeted the headline to her statement:

The Israel Defense Forces’ Gaza division commander, Brig. Gen. Micky Edelstein, said Wednesday that Palestinian terrorists have set more than a thousand IEDs during the current conflict and that after his soldiers swept a single Gaza street comprising 28 buildings, 19 were found to have been booby-trapped, the Times of Israel reported.