The deputy to Osama Bin Laden said in the video, aired on al-Jazeera television, that only jihad, or holy war, would "liberate Palestine".

Palestinian President Mahmoud Abbas last weekend called for new elections.

His Fatah party is locked in a struggle with Hamas, which won elections in January and opposes new polls.

Second truce

Zawahiri says in the video: "Any road other than jihad will only lead to loss.

"Those trying to liberate the land of Islam through elections based on secular constitutions... will not liberate a grain of sand of Palestine."

In the video, Zawahiri wore a white robe and black turban, with a rifle behind his shoulder.

Only a few excerpts from the message were initially shown and it was unclear when the video was shot.

Zawahiri said the Palestinians should not "retreat in the face of the West".

Mr Abbas's election call on Saturday sparked violence between Fatah and Hamas militants.

A second ceasefire was called on Tuesday evening after Sunday's truce failed to end the bloodshed.

Mr Abbas and Prime Minister Ismail Haniya, of Hamas, have both appealed for calm.

Fighting between the factions has paralysed the Hamas administration, which has also been crippled by an international embargo against it.

Photo Caption

Ayman al-Zawahiri