Chaos has erupted on the second day of aid operations by a new U.S.-backed group in Gaza. Palestinians overwhelmed a center distributing food on Tuesday, breaking through fences. An AP journalist heard tank and gunfire from nearby Israeli troops and saw a military helicopter firing flares. The Israeli military said its troops fired warning shots in the area outside the center to bring the situation under control. At least three injured Palestinians were seen being brought from the scene. The distribution hub outside Rafah had been opened the day before by the Gaza Humanitarian Foundation, which has been slated by Israel to take over aid operations despite opposition from the U.N. and other humanitarian organizations.