US President Barack Obama's administration today renewed calls on China to free democracy campaigner Liu Xiaobo but stayed mum on a bid to rename a Washington street after him. 

Beijing has warned the United States against the bid in Congress to name the street outside China's embassy in honour of Liu, a writer who was sentenced in 2009 to 11 years in prison for spearheading a bold petition for democratic reforms.

State Department spokeswoman Marie Harf said that Liu -- whose wife Liu Xia has been under house arrest since her husband won the Nobel Peace Prize in 2010 -- "has played an important role in advancing dialogue in China." 

Liu Xiaobo "has been a voice, should be released from prison (and) his wife's house arrest should end," Harf told reporters.

But on the proposal over the street, Harf said: "Publicly, we're not taking a position on it at this time."

Lawmakers from across the political spectrum have supported calls to rename the street. The House Appropriations Committee approved the change yesterday as part of a State Department funding bill, which still needs backing from the full House of Representatives and Senate.