Liu was allowed to leave the Beijing apartment where she has been held for two-and-a-half years to attend the trial of her brother on fraud charges that his lawyers said are trumped up to punish the family. Taken by car into the court in Beijing's suburbs, she sat through the morning-long proceedings, and when she came out accompanied by her lawyer, she shouted from an open window at diplomats and reporters.
"I'm not free. When they tell you I'm free, tell them I'm not," she said.
The brief exchange is one of the few instances when Liu has broken the security cordon that has surrounded her. A poet and activist in her own right, Liu became an exponent for democracy and freedom of expression after her husband was jailed in late 2008 for authoring and disseminating a program for political reform called Charter '08.
Liu Xiaobo was later sentenced to 11 years in prison, his fourth prison term in 20 years of political activism. Since he was awarded the Nobel in 2010, authorities have tried to turn Liu Xia into a non-entity to prevent her from becoming a rallying point for Chinese seeking democratic change.
Authorities in China routinely put pressure on family members of political activists and government critics to cow them into falling in line.
Twice in recent months outsiders have managed to slip past police to visit Liu Xia in her apartment, a group of Associated Press reporters in December and then five political activists several weeks later.
Lawyers and family members said the charges against her brother, Liu Hui, appear to be in retaliation for those visits. The charges relate to a real estate deal in which prosecutors said Liu and a partner pocketed 3 million yuan ($500,000) that was claimed by another party to the transaction.
His attorneys said the funds have been returned and the dispute does not rise to the level of crime.