Israel said it had resumed enforcing a Gaza ceasefire after carrying out dozens of deadly strikes on Hamas positions Sunday, having accused the group of targeting its troops in the most serious violence since the 9-day-old truce began. Gaza's civil defense agency, which operates under Hamas authority, said at least 45 people had been killed across the territory in Israeli strikes. Four hospitals in Gaza confirmed the death toll of 45, saying they had received the dead and wounded.