Moroccan police is said to have placed Aminatou Haidar, the Western Sahara independence activist, under house arrest.
Police has surrounded her house since her return to her desert homeland after a hunger strike in a Spanish airport.
She vowed to step up her struggle for human rights in the former Spanish territory despite what she called Moroccan repression.
Moroccan officials say Rabat is committed to respecting human rights in Western Sahara and elsewhere in the country. They declined to comment further on Haidar's case.
Western Sahara enjoys lucrative phosphate reserves and potentially offshore oil. It is also is the scene of Africa's longest-running territorial dispute.
Last week, Haidar, a 43-year-old mother-of-two, ended a month-long hunger strike in a Spanish airport in protest at Rabat's refusal to let her back into Western Sahara unless she declared her loyalty to the Moroccan king.
Morocco let her return home after the US, Spain and other countries intervened.
"I have the courage of my conviction to carry on with the defence of the cause of self-determination of the Sahrawi people. I will never waver despite the threats of jail, abduction, torture and exile," she says.
Haidar's fasting focused international attention on Western Sahara's dispute in a way rarely seen in the 35 years since Morocco annexed the territory after Spain pulled out.
"The siege is continuing. I am under house arrest. Family members and neighbours have problems visiting me. Shops in my neighbourhood are suffering from the siege," Haidar told Reuters by telephone on Wednesday.
Reuters reporters were denied access to Haidar by security forces. Other journalists have also been prevented from meeting Haidar.
Haidar accuses Morocco of pursuing a "carrot-and-the stick" policy towards Algeria-based Polisario Front and the Sahrawis in the territory.
"Morocco represses the Sahrawi population while it is negotiating with the Polisario Front," she says.
Morocco said it is ready to resume negotiations with the Polisario on a deal on the future of the territory. Rabat has offered autonomy.
The Polisario, which seeks an independent state in the territory, also wants the talks to resume but it insists that Rabat halts what it called its widespread abuses of human rights in Western Sahara.
Haidar has become "symbol of a nation" for Sahrawis in Western Sahara as well as in refugee camps in the Algerian southwestern area of Tindouf.
Many Sahrawis see her hunger strike as breathing a new life into their cause.
"Before Aminatou, the cause reached a deadlock. There was no hope for a solution. But Aminatou's action put back the Western Sahara's issue at the top of the international agenda," El Bachir El Dhif, a Sahrawi journalist, said.
According to 2005 census, Western Sahara's population is estimated at 383,000, 25 per cent of them living in camps like the Tanduf camp in Algeria.