"It is a matter falls within China's judicial sovereignty. She is a Chinese national (and) we of course handle the relevant issue in accordance with our laws and regulations," Liu said at a regularly scheduled news conference.
Lu's comments came after writers and artists including South African novelist and Nobel winner J.M. Coetzee, Rita Dove, Paul Auster, Khaled Hosseini and Michael Chabon read excerpts of Liu Xia's poetry as part of a video campaign. Liu Xiaobo died of cancer last year while serving a prison sentence for incitement to subvert government power.
Liu Xia, who suffers from depression and is believed to be in declining health, has never been charged with a crime, but has been kept guarded and isolated since her husband was awarded the 2010 prize.
In a news release about the video readings, Amnesty International said: "The excerpts celebrate some of Liu Xia's most powerful works while calling on the Chinese government to end their cruel campaign of retaliation against her for her late husband Liu Xiaobo's calls for democratic reform."
Germany said earlier this month it would welcome Liu after a recording was released of her crying in desperation and indicating she has given up hope of being able to leave China. "If I can't leave, I'll die in my home," Liu said during the recent phone call with her close friend Liao Yiwu, a writer who documented their conversation.