Authorities in the Chinese capital are holding Tibetan poet and author Tsering Woeser and her dissident writer husband Wang Lixiong under house arrest during a visit to Beijing by a U.S. non-government group, Woeser said via Twitter.
Wang and Woeser have been prevented from leaving their Beijing home by state security police since Monday, and the restrictions will remain in place until Friday, Woeser wrote.
"The Beijing state security police told us that it's because of a delegation from the American Himalayan Foundation which arrived in Beijing [on Monday]," she wrote.
"I hope that the American Himalayan Foundation will come to hear of our house arrest during their visit," she said, adding: "I had never heard of this organization."
Woeser and Wang have already been prevented from leaving China, with Wang prevented from boarding a plane for Japan by border guards at Beijing's Capital International Airport in December.
Repeated calls to Woeser's phone and to the American Himalayan Foundation, rang unanswered on Tuesday.
The foundation builds schools, trains healthcare professionals, subsidizes education and healthcare and helps protect cultural artifacts and the environment across the Himalayan region, according to its official website.
It also funds campaigns to stop the trafficking of girls and to save tigers.
Woeser has used her blog "Invisible Tibet," together with poetry, historical research, and social media platforms to give voice to millions of ethnic Tibetans who are prevented from expressing themselves to the outside world by government curbs on information.
In a recent commentary written for RFA's Mandarin Service, she hit out at the politicization of a centuries-old Tibetan Buddhist dispute by the ruling Chinese Communist Party.
Wang has written several works on Tibetan issues, including Sky Burial: The Fate of Tibet, and has also spoken out about the large-scale losses to Tibetan culture during the state-sponsored destruction of the Cultural Revolution.
In a recent commentary broadcast on RFA's Mandarin Service, he detailed the ruling Chinese Communist Party's mass killing of Tibetan rebels following the arrival of the People's Liberation Army (PLA) in the region in 1950 and the policies of "class struggle" that divided Tibetan society against itself.
Wang is best-known for his 1991 apocalyptic political parable "Yellow Peril" which prophesies a China embroiled in political, economic, cultural, demographic and ecological crisis and the country's collapse. The novel and his nine other books are banned in mainland China.
Reported by Hai Nan for RFA's Cantonese Service. Translated and written in English by Luisetta Mudie.