"The Sahrawi people who led a murderous war for their freedom have always been characterised by their wish for peace, without ever resorting to terrorism, which they reject, being in contradiction with their values and traditions," he wrote in a letter to Bush.

He called on the US leader to intervene to obtain the release of 33 Sahrawi political prisoners who he said have been imprisoned in Morocco since 21 May, according to excerpts of the letter published by the Sahrawi news agency SPS carried by its Algerian counterpart APS.

The Algerian-backed Polisario Front also says that Morocco still has 150 prisoners of war and more than 500 missing who are being held in secret in Moroccan prisons.

Prisoners' release

Polisario's release of 404 prisoners - some held for two decades - last Thursday under US mediation was hailed by the international community and prompted calls for Morocco to reciprocate and renewed efforts to resolve the 30-year-old conflict.

"The great tragedy of the Sahrawi people, as well as the people of the region [began with] the Moroccan military invasion of Western Sahara on 31 October 1975," Abdelaziz said in the letter, dated 18 August.

The Western Sahara is a former Spanish colony whose annexation by Morocco triggered the hostilities.