Three Palestinian fishermen were killed Sunday after a blast ripped through their boat off the Gaza shore, union officials said. Nezar Ayyash, of the fishermen syndicate, said the anglers – two brothers and a cousin – were plying their trade off the coast of the city of Khan Younis in southern Gaza Strip when the explosion happened, as The Associated Press (AP) reported.

The cause of the blast was not immediately clear. Palestinian media reports blamed the Israeli navy fire, but the Israeli military said it was not involved in this incident. The Hamas-run interior ministry in Gaza said it opened an investigation.

"The three men were martyred when a missile fell on their boat in the Mediterranean Sea off the shores of the southern Gaza Strip,” Nizar Ayyash, the head of the Palestinian Union of Fishermen, said, according to remarks carried by Anadolu Agency (AA).