By Stephanie Irvine BBC North Africa correspondent

The Moroccan soldiers being held captive in Algeria by the Polisario Front independence movement are the longest serving prisoners of war in the world, still held in spite of an 11-year-old ceasefire.

As the UN's peace mission in Western Sahara extends its mandate for another three months, families wait for the release of prisoners being held hostage to a stalled political process.

Latifa Johari shows me a photograph of her and her husband back in 1975 - carefree young newly-weds, hand in hand, going out on the town.

Ahmed Azazar, freed after 21 years

Two months later, her husband Ahmed Ben Boubker, a fighter pilot in the Moroccan Air Force, was captured by the Polisario Front in Western Sahara and taken prisoner.

Another photograph, taken by the International Red Cross, shows him now, 27 years later, in the Polisario's prison camp in western Algeria.

"I go from hope to despair. Sometimes there are rumours that some prisoners will be released, and my daughter and I think maybe he'll be one of them.

"We're overcome with excitement, we do up the house, but then he doesn't come and we're right back where we started."

We were treated like animals

Ahmed Azazar, former POW

Ahmed Ben Boubker is one of 1,362 Moroccans still held captive by the Polisario Front, most of them for over 20 years.

The two sides were fighting over Western Sahara, a former Spanish colony over which Morocco claims sovereignty.

When the Spanish left in 1976, Morocco took over control.

Local Saharawi people opposed to Moroccan rule formed the Polisario Front, and with military backing from Algeria, fought a war of independence against Morocco, until a United Nations peace mission brokered a ceasefire in 1991.

According to the Geneva Convention all the prisoners should have been released then.

Waiting for referendum

But the Polisario Front says it will release them only in the framework of the UN peace plan which promised a referendum on independence.

That vote has not taken place - blocked, says the Polisario, by Morocco.

The Polisario also complains of human rights abuses against Saharawis in Western Sahara, and says that the fate of disappeared Saharawis must be investigated.

Many of them have never seen their children

Pierre Rytter ICRC delegate

The Polisario has freed some prisoners over the years in what it describes as a gesture of goodwill.

Those released, complain of the harsh conditions in the camps.

"We were treated like animals," says Ahmed Azazar, who was 70 when he was let out two years ago, after 21 years.

"We had nothing to eat, no clothes to wear, and we were forced to work from dawn till dusk."

Access to camps

The International Committee of the Red Cross (ICRC) gained access to the camps in 1994, and was able to bring the prisoners letters and photographs from home.

"Many of them have never seen their children, or the children were very young when they were captured," says Pierre Rytter, ICRC's North Africa delegate.

Waiting wives: Staying cheerful in the face of adversity

"You can imagine the emotion of a father who sees his child for the first time, because some did not receive any pictures for 20 years."

The ICRC is concerned about the physical and mental health of those detained, and it is lobbying for their release.

It says the humanitarian issue of the prisoners should be dealt with separately from the political question of the future of Western Sahara.

On the latter there has been little progress.

The United Nations is considering three options, including autonomy for Western Sahara under Moroccan sovereignty, or imposition of the original plan for a referendum.

But the UN was unable to reach a decision by the last deadline of the end of April, so it has extended its mandate in the territory to the end of July.

While the political negotiations continue, the days pass slowly for the world's longest serving prisoners of war, and their families.