China is rejecting international calls to release imprisoned Nobel Peace Prize winner Liu Xiabao.

Chinese Foreign Ministry spokesperson Hong Lei said Friday that the dissident writer “broke Chinese laws and should be punished as a consequence by law.”

On Thursday, Amnesty International and Human Rights Watch issued statements calling for Liu's release, almost a year after he received the award. Five Nobel Peace Prize recipients also called for renewed efforts to obtain his release.

Liu was sentenced to 11 years in prison in 2009 for allegedly inciting subversion of state power after he published a manifesto for democratic changes in China. Rights groups say this is a charge often used to eliminate dissenters.

Amnesty International's Asia-Pacific deputy director Catherine Baber said the increasingly powerful police and security forces in China act with impunity as they hold individuals beyond legal supervision, often torturing and ill-treating them.

Sophie Richardson, China Director for Human Rights Watch in New York, said it is time for China to make progress on individual human rights cases. .

The U.S. Congressional-Executive Commission on China heard a series of witnesses Tuesday to mark Liu's award ceremony, which he was not able to attend.

Among the experts testifying at the hearing were Princeton University professor of Asian Studies Perry Link, founder of ChinaAid Association pastor Bob Fu, President of the National Endowment for Democracy Carl Gresham, and independent scholar and rights activist Li Xiaorong.