The New Nation - Internet Edition

AFP, Gaza City

Hamas-run security forces fanned out across Gaza City Saturday, clashing with rival gunmen and arresting dozens of people after a bomb blast killed five senior Palestinian militants and a girl of five.

The explosion late on Friday near a beach outside Gaza City was the deadliest incident in weeks in the 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 Fatah movement, accusing it of collaborating with Israel.

"This criminal act proves that the call for dialogue from Ramallah (Abbas's headquarters) was a lie designed to throw sand in our eyes and conceal a conspiracy to kill and assassinate and terrorise our security forces," Hamas said in a statement.

In the hours after the attack, Hamas-run security forces arrested dozens of people in sweeps across Gaza City, mostly Fatah members, according to witnesses.

Heavy fighting took place overnight in Gaza's Tel al-Hawa district, where Hamas gunmen battled with the family of a man they sought to arrest, exchanging gunfire and volleys of rocket-propelled grenades.

A senior Fatah official who asked not to be named said security forces arrested over 100 Fatah members and raided his party's offices across Gaza, confiscating computers and documents.

Most of Abbas's loyalists were driven from Gaza in June 2007 when Hamas seized power following a week of bloody street battles between the rival factions.

In a statement released by Abbas's office Fatah denied any involvement in the "mysterious explosion" and accused elements within the armed wing of Hamas of planting the explosives as part of an internal conflict.

It was the deadliest day in Gaza since a truce was agreed between Hamas and Israel in June which halted what had been near-daily clashes between Palestinian militants and Israeli troops.