Palestinian gunmen planned to assassinate Israeli Prime Minister Ehud Olmert when he came to the West Bank in August to meet with Palestinian President Mahmoud Abbas, a security chief told Israel's Cabinet on Sunday, a meeting participant said.

Shin Bet security police director Yuval Diskin said gunmen loyal to Abbas' Fatah movement planned to attack Olmert's convoy as it entered the West Bank town of Jericho on Aug. 6. Israel notified Palestinian authorities and they arrested an unspecified number of Fatah militants, the participant said.

It was not clear why Israel, whose military operates freely in the West Bank, left it up to Palestinian security sources to apprehend would-be assassins if they thought Olmert's life was in danger — or why they allowed the trip to proceed.

Although the men admitted they planned the attack, the Palestinian Authority released them last week, the meeting participant said, speaking on condition of anonymity because he was not authorized to disclose details of closed-door meetings.

Olmert's office has protested their release to Abbas, he said. Abbas' office said it was looking into the Israeli claims.

Israel Radio said cited a Palestinian security source as saying three men were arrested, questioned for two months, but were released for lack of evidence.

An Israeli government spokeswoman had no immediate information on the assassination attempt, and it was not clear how close the militants got to carrying out the plot. It also was not clear why the assassination plan was released 2 1/2 months after it took place.

Abbas does not control Fatah's armed factions, which frequently act counter to his efforts to reconcile Israel and the Palestinians.

The meeting was Olmert's first with Abbas on Palestinian soil after seven years of bloody fighting, and the location was seen as significant as the content.

Israeli and Palestinian security forces worked together to protect the Israeli leader, and Abbas gained some stature by hosting Olmert by leveling what is widely seen as an uneven relationship. Every other meeting has been held at Olmert's Jerusalem residence.