"This catastrophe shows once again that the Sahrawi issue must be solved as soon as possible," Polisario Front President Mohamed Abdelaziz told Reuters.

"The time has come to pressure Morocco to accept the referendum solution as the only and unique solution," he said, referring to a plan to allow Sahrawis to vote on whether they want the territory to remain part of Morocco.

Morocco seized most of Western Sahara after Spain withdrew in 1975, claiming historical rights to the mineral-rich desert territory which may also have offshore oil deposits.

The move triggered a 16-year war with the Algerian-backed Polisario, which set up the Sahrawi Arab Democratic Republic in 1976 and wants independence for the region.

The UN-mediated truce came with the pledge of a referendum on Western Sahara, but Morocco has refused to allow a vote on self-determination. Polisario's principal backer is Algeria.

The Sahrawi refugees live in five camps in the desert near the border, totally dependent on outside assistance.

"We are used to catastrophes. It makes us stronger. I thank Algeria and the international community for the aid and support to the Sahrawi refugees living in the camps," Abdelaziz said.

In Geneva, the UN refugee agency said it would start flying in emergency aid on Friday from Jordan.

"Dozens of flights are needed during the coming week to quickly bring more than 2,000 light-weight tents, blankets, mattresses, plastic sheets and jerry cans to the affected refugees," a UNHCR statement said.

Fifty percent of the shelters in three of the five camps - Awserd, Smara and Laayoune - were destroyed, and 25 percent were severely damaged, the agency said.

"Half of the infrastructure of the (three) camps has also collapsed - none of the clinics can be used, most hospitals, their pharmacies and equipment are heavily damaged and all schools have been destroyed," it said.

Many Sahrawis said they are optimistic a solution will be found to the dispute, which has been a constant cause of friction between Algeria and Morocco and a major obstacle to ambitious plans for regional trade and political integration.