Image copyright Getty Images Image caption Supporters have appealed to China to allow Mr Liu to travel abroad for treatment

Two Western doctors have contradicted Chinese medical experts over the fate of a dying Nobel Peace Prize winner.

Liu Xiaobo, an imprisoned pro-democracy advocate, was moved to hospital while serving an 11-year jail term, because of his advanced terminal liver cancer.

His doctors in China say he is too ill to travel abroad for treatment, and must remain in China.

But medics from the US and Germany who examined Mr Liu disagree, and say he could go abroad for palliative care.

Joseph Herman from the University of Texas' cancer centre and Markus Büchler of the University of Heidelberg surgery department, released a joint statement saying a medical evacuation would have to happen "as quickly as possible".

Image copyright Posted on Twitter by Guangzhou-based writer Ye Du Image caption Friends of Liu Xiaobo and his wife say he is near death

"While a degree of risk always exists in the movement of any patient, both physicians believe Mr. Liu can be safely transported with appropriate medical evacuation care and support," they said.

Liu Xiaobo and his family have both asked that he be allowed to leave.

Mr Liu was a key leader in the famous Tiananmen Square protests in 1989, and has been a vocal advocate for full democracy in China since.

The state considers him a criminal dissident, and in 2009, sentenced him to 11 years in prison for subversive behaviour after he drafted a manifesto on democracy and human rights.

He was awarded the Nobel peace prize in 2010 for his "long and non-violent struggle".

"Through the severe punishment meted out to him, Liu has become the foremost symbol of this wide-ranging struggle for human rights in China," the Nobel Committee wrote.

He had more than three years remaining on his sentence when authorities moved him into a hospital.

Following his Nobel prize, Mr Liu's wife, a poet, was placed under house arrest, and has had her movements restricted ever since. She has never been charged with a crime.

Full Story: The love that survived a Chinese labour camp

By Celia Hatton, BBC News

Image copyright Supplied

"I found all the beauty in the world in this one woman."

Their wedding banquet was in the labour camp's cafeteria, a scenario that would prove to be symbolic. Throughout their intense romance, the Chinese government was a relentless and interfering third wheel, the uninvited partner providing a constant backdrop to their interactions.

By all accounts, Liu Xiaobo and Liu Xia were inseparable, except when they were forcibly separated.