The Polisario movement, which is fighting for the independence of Western Sahara, has released a further 243 Moroccan prisoners of war (POWs). They were flown home from neighbouring Algeria on Monday.
The International Committee of the Red Cross (ICRC), which organised the repatriation, said the Moroccans were flown from Tindouf in western Algeria, where they had been held, to a military base near the coastal city of Agadir on a specially chartered plane.
One of those released had been captive for 28 years and was generally believed to be the world's longest serving prisoner of war, it added.
The ICRC said in a statement that Polisario had released 946 Moroccan prisoners in several batches since January 2000, but still held 914. Most of these had been held at prison camps in western Algeria for over 20 years, it noted.
The ICRC and UN Secretary General Koffi Annan welcomed this latest release, but urged Polisario to free immediately all the remaining POWs which it is still holding.
Polisario, which is recognised by many countries as the legitimate government of Western Sahara, began fighting Morocco in 1976 when Spain withdrew its colonial administration from the desert territory and divided it between Morocco and Mauritania.
Mauritania subsequently withdrew its claim to the southern part of Western Sahara which was annexed in its entirety by Morocco.
Morocco and the Polisario agreed a ceasefire in 1991, since then the United Nations has been trying to broker a political settlement acceptable to both sides.
The latest UN plan, devised by former US Secretary of State James Baker earlier this year, offers the inhabitants of the former Spanish colony a referendum on independence, autonomy or full integration with Morocco within five years.
It was accepted by the Polisario and endorsed by the UN Security Council, but has been rejected by Morocco's King Mohamed VI.
However, a UN official in New York told IRIN on Tuesday that quiet diplomacy was still going on to persuade Rabat to change its mind and accept the deal.
Although both sides accept the principle of a referendum they differ in their opinions about who should be entitled to vote on the future of the territory.
Polisario would like to exclude many of the recent Moroccan immigrants to Western Sahara, whereas Morocco would like to prevent many of the Polisario supporters and their offspring who have been living in exile for many years from voting. There is a particularly large pro-Polisario exile community in Algeria.
The UN mandate to try and find a solution to the 27-year-old dispute has been extended until October 31 to provide a little more time to broker a deal.
On 5 August, Annan appointed Alvaro de Soto of Peru as his new special representative for the Western Sahara. He replaced William Swing, an American, who was reassigned to become the UN Secretary General's Special Representative for the Democratic Republic of Congo.
The latest release of POW's by Polisario was announced on August 14 and followed the freeing of 100 Moroccan prisoners in February.