Large craters and a bomb fragment from an Israeli airstrike on a camp for displaced people early Tuesday provide strong evidence that Israel used 2,000-pound bombs, according to three weapons experts.

The United States has previously warned Israel that the powerful munitions can cause excessive civilian casualties in the densely populated Gaza Strip, and suspended exporting U.S.-made 2,000-pound bombs to Israel earlier this year.

Israel said it had carried out “precise strikes” aimed at Hamas militants, but has so far declined to say what sort of bombs were used. At least 19 people were killed in the blasts and more than 60 others injured, Gazan authorities said, a toll that appeared likely to rise. Health officials in Gaza do not distinguish between civilians and combatants when reporting casualties.

Video filmed after the attack and verified by The New York Times showed two enormous blast craters measuring close to 50 feet wide. Satellite imagery captured on Monday showed no craters at the location, confirming they were new.

One of the weapons experts — Chris Cobb-Smith, a former British Army artillery officer and director of Chiron Resources, a security and logistics agency told The Times that the dimensions of the craters were broadly consistent with the use of 2,000-pound munitions.