Contrary to claims by Morocco, there are few rights abuses at refugee camps run by the pro-independence Polisario movement in Western Sahara, Human Rights Watch said Saturday in a new report.

In its two week investigation of the camp, which included interviews with residents, the organization noted isolated cases of harassment of critics and use of military courts against civilians, but in general found camp residents could freely express themselves or leave.

"There are cases of abuse, but there has also been exaggeration by some parties," said Sarah Leah Whitson, Human Rights Watch's North Africa director, in a clear reference to Moroccan allegations of persistent rights violations.

The camps in the remote desert region of Tindouf in Algeria hold some 90,000 refugees from the Western Sahara, which was annexed by Morocco in 1975.

Morocco fought a 15-year war against the Polisario, until a U.N.-brokered ceasefire in 1991 paved the way for a referendum to determine the territory's fate. Morocco has blocked the referendum and offered instead a wide-ranging autonomy plan.

Human rights groups accuse Morocco of using violence to stifle dissent and restrict freedom of expression in the Western Sahara.

There have been several attempts to grant a U.N. mission the power to monitor the human rights situation in the camps and in Moroccan-controlled Western Sahara, but these have been opposed by Morocco as a violation of its sovereignty.

Visits by rights monitoring agencies to the camps are sporadic, in part, due to their remoteness, according to the Human Rights Watch report.