A Morocco court has sentenced 23 civilians to prison terms ranging from two years to life over the killing of 11 members of the Moroccan security forces in contested Western Sahara.

A verdict was delivered at dawn on Wednesday by the Court of Appeals in Sale near Rabat, the official news agency MAP reported.

The defendants and lawyers have boycotted court proceedings since May, announcing they would no longer attend what they said was a "mock trial".

The killings took place in November 2010 as Moroccan forces moved to dismantle a camp in Gdim Izik camp where thousands of displaced Western Saharans, known as Sahrawis, were living.

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Morocco and the Algeria-backed Polisario Front independence movement have accused each other of provoking the deadly clashes, which spread to a nearby city where businesses and public buildings were looted and torched.

The defence has 10 days to appeal.

The defendants, who include several advocates of human rights and independence for Western Sahara, were initially tried by a military court in 2013, and sentenced to jail terms ranging from 20 years to life imprisonment.

International rights groups condemned the trial as unfair, saying allegations of forced confessions were never addressed, leading the court of cassation to order a retrial.

The civilian court issued its verdict on Wednesday after 12 hours of deliberations, issuing sentences against 19 defendants ranging from 20 years to life.

Four others were given lighter sentences but were not detained as they had already served their time.

The international rights monitors Amnesty International and Human Rights Watch issued a joint plea this week urging the Moroccan authorities to ensure that the verdict was not based on confessions or statements "obtained under torture or other ill-treatment during police interrogations".

The Moroccan authorities have sought to underline what they called the "transparency" and "fairness" of the civil trial, which was open to the press and international observers.

Morocco says Western Sahara, a former Spanish colony mostly controlled by Rabat, is an integral part of the kingdom.

The Polisario Front demands a referendum on self-determination for the territory.