Palestinian leader Mahmoud Abbas was elected president of Palestine on Sunday by a key decision-making body of the PLO, amid tensions with rival Islamists, officials said.

The symbolic vote was taken at a meeting of the Palestine Liberation Organisation's (PLO) 120-member central council.

"I announce that the PLO central council has elected Mahmoud Abbas president of the state of Palestine. He takes on this role from this day, November 23, 2008," the body's chairman Salem Al Zaanun told reporters.

He said the vote was taken on a proposal from 75 members of the council.

"After a democratic debate, this proposal was adopted nearly unanimously, with only one member voting against," he said, without giving the exact number of participants. Abbas,73, is already president of the Palestinian Authority (PA) but his four-year term of office expires on January 8.

The move is expected to strengthen his standing with his rivals in the Islamist movement Hamas, who have threatened to stop recognising Abbas' authority from January 9.

Abbas is also chairman of the PLO which is negotiating peace with Israel and head of the mainstream Fateh Party.

Since June 2007, Hamas has controled the Gaza Strip after violent clashes which drove out Fateh from the impoverished territory.

The move has divided the Palestinians, with Abbas' power practically confined only to the Israeli-occupied West Bank where his headquarters are located.

Earlier on Sunday, Abbas threatened to call snap presidential and parliamentary elections in the new year if there is no agreement with the Hamas to end the rift in Palestinian ranks.

"If the dialogue does not succeed, then at the start of next year we will issue a presidential decree calling parliamentary and presidential elections," Abbas told the central council, which has the power to dissolve the PA.

But Hamas swiftly rejected his threat, saying he had no powers to dissolve the current parliament in which they won a large majority in the last elections in 2006.