Hamas and Fatah are killing each other again: Hamas hunts down Fatah rivals after Gaza blast.

GAZA CITY (AFP) - Hamas-run security forces stormed across Gaza on Saturday, clashing with rival Palestinian gunmen and arresting dozens of people after a bomb killed five of its senior militants and a little girl.

The explosion late on Friday near a beach outside Gaza City was the deadliest incident in weeks in the impoverished Palestinian territory which has been ruled by the Islamist Hamas movement for more than a year.

The cause of the explosion was not immediately known but Hamas blamed Palestinian president Mahmud Abbas’s rival Fatah movement, accusing it of collaborating with Israel to undermine the Islamist movement.

“The Fatah movement is behind this reprehensible crime,” senior Hamas leader Khalil al-Haya told a crowd of thousands of supporters and other senior leaders at a funeral for those killed.

“Those who carried out this crime are making war on God, on the security of Gaza, and on the resistance,” he said. “They will not be released after six months but will be hanged from the gallows and shot.”