Aminatou Haidar was arrested and held for 22 hours by Moroccan authorities at the airport on her return to Western Sahara, the Dublin-based Front Line human rights group said. After she refused to recognize Moroccan nationality, she was deported this weekend to Spain's Canary Islands, the group said.

Morocco claims the disputed Western Sahara, while the Polisario Front rebel group wants independence for the territory. U.N.-brokered talks have failed to resolve the decades-long dispute.

Haidar was stopped on her return from the United States, where she was awarded the Train Foundation's Civil Courage Prize. The group honored her "courageous campaign for self-determination of Western Sahara from its occupation by Morocco, and against forced disappearances and abuses of prisoners of conscience." She has spent time in Moroccan prisons.

Moroccan Foreign Affairs Minister Taieb Fassi Fihri denied that Haidar had been arrested or pressured, according to the official MAP news agency. He said she refused to recognize her Moroccan nationality at the airport and then "took a plane" to leave.

The issue of nationality is sensitive. Moroccan King Mohammed VI recently gave a speech with pointed comments for Sahrawi activists, saying, "Either a person is Moroccan, or is not ... One is either a patriot, or a traitor."

Human Rights Watch also expressed concern about Haidar.

"This is part of a new hardline policy by the Moroccan authorities to clamp down on advocates of self-determination for Western Sahara," said Eric Goldstein, Human Rights Watch deputy director for the Middle East and North Africa.

Morocco has also been restricting "unauthorized" visits by foreigners, including journalists and human rights lawyers, to the homes of Sahrawi activists in Western Sahara, he said.