GAZA—Three Palestinian fishermen who died in an offshore blast on Sunday had encountered an explosive-laden Israeli drone that had fallen into the sea and blew up in their nets, the Hamas-run Interior Ministry in Gaza said on Thursday. An Israeli military spokeswoman had no immediate comment. At the time of the blast, the Israeli military had denied it had any involvement in the incident. The incident came at a time when Palestinian terrorists have been test-firing rockets into the sea, and a Gaza-based human rights group, the Palestinian Center for Human Rights, said on Sunday the fishing boat may have been hit by accident. But Eyad Al-Bozom, the Gaza Interior Ministry’s spokesman, said no Palestinian rocket had hit the fishing boat, and that parts of an Israeli quadcopter drone that carried explosives were discovered in its nets. The drone had blown up as the fishermen were lifting their nets, killing all …