Liu won the prize for his decades of promoting democratic change in China. He is serving an 11-year prison sentence for subversion.
Some of Liu's supporters say they received threatening phone calls from police before they released a letter yesterday calling for Liu to be freed.
Beijing police have not immediately responded today to a faxed question about the complaints of harassment.
China's state-run media has reacted angrily to the peace prize, calling it a tool the West is using to undermine China.
Published 15 October 2010, 12:50 IST