Elections must be held simultaneously in the West Bank and Gaza Strip, President Mahmoud Abbas said Thursday.

It is "not acceptable to hold them in the West Bank only," Abbas said.

At a news conference alongside President of East Timor Jose Ramos-Horta, Abbas said efforts would be made to ensure that the vote could go forward by September in all Palestinian areas.

Last week, the Palestinian Authority announced it would hold presidential and legislative elections by September. A local election is also scheduled to take place on July 9.

But the Islamist movement Hamas, a sworn enemy of Abbas's secular Fatah faction which dominates the Palestinian Authority, has rejected the call for elections.

It says Hamas will not participate without a reconciliation deal between the two warring factions.

"Abbas's declaration that there would be no elections without Gaza, despite the fact that several days ago they said the elections would take place in any event, proves that they are in a state of confusion," said Sami Abu Zuhri, a spokesman for the movement.

The issue of reconciliation dialogue needed to be completely reexamined, he said, but elections "would be the result of any solution, and not the cause of one."

The rivalry between Hamas and Fatah dates back to the early 1990s. The situation deteriorated dramatically after the Islamist movement won elections in 2006 and, a year later, seized control of Gaza after deadly street fighting with Fatah.

Since then, the Palestinian territories have been effectively split in two, with Abbas's rule confined to the West Bank.

Repeated attempts at getting the two parties to reconcile their differences have led nowhere, and the Mubarak regime, which played a key role in reconciliation efforts, is now firmly out of the picture.