JERUSALEM, Sept 4 (Reuters) - Israel intends to release from prison 100 members of Palestinian President Mahmoud Abbas's Fatah faction as part of U.S.-backed efforts to bolster him, an Israeli government source said on Tuesday. "The idea is to do it before Ramadan," said the source, referring to the Muslim fasting month that begins with the sighting of the new moon in about a week. Olmert's office declined to comment. The source said the 100 Fatah members set to go free come from the Gaza Strip, which Hamas Islamists seized by force in June. The 100 prisoners, the source said, have "no blood on their hands" and at least one year left on their sentences and would be released on condition they signed a document promising not to be involved in violence. Israel freed more than 250 Palestinian prisoners, mostly Fatah members, on July 20, in a bid to boost Abbas, who is engaged with Olmert in preparations for a U.S.-proposed Middle East conference expected in November. The prisoners issue is highly emotive for Palestinians, who see their 11,000 brethren held in Israeli jails as fighters for freedom from Israeli occupation in the West Bank.