RAMALLAH, July 31, 2008 (AFP) - President Mahmud Abbas has ordered the release of Islamist Hamas militants arrested by his forces in the West Bank over the past week, the Palestinian Authority said on Thursday.

'President Abbas has ordered his security officials to free all the Hamas militants arrested in recent days in the West Bank,' it said in a statement.

Five members of the Ezzedine al-Qassam Brigades, Hamas's military wing, and a little girl were killed last Friday by a bomb in the Gaza Strip.

Hamas blamed Abbas's supporters and began a massive crackdown across Gaza, arresting more than 300 people, mostly members of the president's Fatah party.

Fatah denied involvement in the blast and blamed it on internal differences in Hamas.

Abbas's forces in the occupied West Bank responded with an arrest campaign of their own in which dozens of Hamas members were rounded up, though both sides adamantly deny arresting anyone for political reasons.

The two main Palestinian factions have been deeply divided since Hamas expelled Abba's security forces from Gaza in a week of bloody street battles in June 2007, cleaving the territories into rival entities.