Palestinian President Mahmoud Abbas called on Tuesday for a referendum to resolve a power struggle with Hamas, highlighting bitter divisions on a day of mourning for Yasser Arafat.

Tens of thousands gathered at Arafat's gravesite in the West Bank city of Ramallah for the fourth anniversary of the former Palestinian leader's death. Hamas, which seized Gaza last year after routing Abbas's forces, barred Arafat memorials there.

Abbas, who controls the West Bank, and Hamas have traded blame since reconciliation efforts broke down last week. Egypt postponed talks meant to end the rift when Hamas decided to boycott, demanding Fatah release prisoners.

A key dispute is over when to hold an election.

Abbas has proposed holding a simultaneous presidential and parliamentary poll in the Gaza Strip and the occupied West Bank, arguing the law gives him the right to remain in office until 2010.

Hamas demands presidential elections by January 9 when it says Abbas' four-year term ends, but objects to an early parliamentary poll. Hamas won control of parliament in 2006 and argues its lawmakers should serve a full four years until 2010.

Abbas suggested putting the decision about when to hold elections to the general public.

"If they (Hamas) are self-confident, let them accept elections. If they don't, we will seek a referendum," Abbas told the crowd. "We will go back to the people to resolve the crisis," by deciding whether an early parliamentary and presidential poll should be held, Abbas said.

Islamist Hamas said Palestinians can no longer trust Abbas, who heads the secular Fatah movement, as leader.

"He can no longer be trusted with the rights of our people," Fawzi Barhoum, a Hamas spokesman said. "We cannot build hopes for the success of the dialogue and this brings us closer to not giving him another chance to decide our people's fate."

A statement issued by Hamas Interior Minister Said Seyyam in Gaza said: "President Abbas's speech shows that he and his colleagues at the Muqata in Ramallah are suffering from a moral and psychological crisis."

Abbas called on Arab leaders to intervene in the dispute. "Let the Arabs act and we will accept their position, whatever it is," he said.