More than 170 nongovernmental organizations called on Tuesday for a U.S.- and Israeli-backed food aid distribution plan in the Gaza Strip to be dismantled over concerns it is putting civilians at risk of death and injury.

More than 500 people have been killed in mass shootings near aid distribution centers or transport routes guarded by Israeli forces since the Gaza Humanitarian Foundation started operating in late May, according to medical authorities in Gaza.

The GHF uses private U.S. security and logistics companies to get supplies into Gaza, largely bypassing a U.N.-led system that Israel says had let militants divert aid. The United Nations has called the plan "inherently unsafe" and a violation of humanitarian impartiality rules.