"A large number of police" arrived early on Monday, said Hamoudi Igulid, a local representative of the Moroccan association of human rights (AMDH).
"The situation is calm as it is Ramadan," he said. The Muslim holy month will end this week.
Over the past week, skirmishes have taken place almost daily between stone-throwing teenagers and police wielding clubs to disperse the anti-Morocco protesters, and one person has died, Igulid and local residents said.
The outbreak of violent protests comes days before the 30th anniversary of the Green March, launched by Moroccan King Hassan II on 6 November 1975.
On that date, 350,000 Moroccans marched to the border with Western Sahara in a show of support for Morocco's claim to the territory.
Death sparks protest
On Saturday, a young Western Saharan man, Hamdi Lambarki, died of head injuries after probably being hit with a stone thrown by the demonstrators, according to police.
Witnesses, however, gave the victim's family a different account, saying Lambarki was knocked down by a police car and then hit on the head by the authorities.
New protests were sparked by
the death of a Sahrawi youth
Lambarki was taken to hospital in a coma and he died early on Sunday, a police source said, adding that the prosecutor had opened an inquiry into his death.
Lambarki's death sparked a new round of anti-Moroccan protests late on Sunday, Igulid said.
Police arrested a number of young people and the president of the Saharan association of human rights, Brahim Dahane, has been missing since Saturday, he added.
Dahane "was arrested by the police near his home, and since then we have had no further news" about him, Igulid said.
The communications minister for Western Sahara, Nabil Benabdellah, on Monday denied that Dahane has disappeared, insisting that the state "acts in strict accordance with the law".
He confirmed that arrests were made among the protesters, notably among "a small group pushing separatist ideas and using violence".
James Baker was behind a UN
proposal for W Saharan autonomy
Morocco annexed the Western Sahara in 1975, but its claim is contested by the Polisario Front, an Algerian-backed independence movement.
Rabat dismissed the last United Nations proposal for a five-year period of autonomy followed by a self-determination referendum - the Baker Plan named after US former secretary of state James Baker, who threw in the towel in June 2004, expressing frustration over lack of progress.