"She is currently under de facto house arrest back in her apartment in Beijing," said Beth Schwanke, legislative counsel for the US-based group Freedom Now, speaking of the dissident's wife, Liu Xia.
Schwanke said that she learned of the arrest of Liu Xia, whom she said is being held incommunicado, from a reliable source in China.
"We have a source who is able to confirm that this is absolutely accurate," she said.
A second group, Human Rights in China, announced today that it also had received word of Liu Xia's arrest and said in a statement that it "strongly urges the international community to press the Chinese authorities to immediately release Liu Xia from house arrest, free Liu Xiaobo, and free all prisoners of conscience incarcerated as a result of exercising their right of freedom of expression."
Schwanke told AFP that after it was announced Friday that her husband had been awarded the Nobel prize, Liu's phone was taken away by Chinese authorities and she was detained.
The detention took place after Liu Xia had been taken to see her husband in prison and permitted to tell him that he had won the Nobel.
"She was taken there on Saturday and she was allowed to see him on Sunday," the spokeswoman said."After she returned to Beijing they told her that she would not be allowed to leave her apartment," Schwanke said.
"I understand that he cried and said that this is for the martyrs of Tiananmen Square," said Schwanke.
"After that, she was taken back to Beijing and she was put under de facto house arrest," she said. "She's not allowed to leave her apartment and her phone has actually been destroyed.
Liu, the first Chinese citizen to win the Nobel Peace Prize, is a 54-year-old writer imprisoned since December after authoring Charter 08, a manifesto signed by thousands seeking greater rights in the communist nation.