An explosion in a Beirut suburb Tuesday killed Saleh Arouri, a senior Hamas official, the group said. A U.S. defense official, speaking on the condition of anonymity to discuss sensitive operations, said the Israel Defense Forces was responsible for a strike targeting Arouri and that an assessment of whether he had been killed was ongoing. At least six people died in the explosion, Lebanon’s state news agency reported. Hamas said Israel had carried out “cowardly assassinations” and that two leaders of Hamas’s elite Izzedine al-Qassam Brigades had also been killed. The IDF declined to comment on the blast and Israel has not claimed responsibility for the attack.