"Liu Xiaobo and his family have requested that the remainder of his care be provided in Germany or the United States," said Dr. Joseph M. Herman of the University of Texas MD Anderson Cancer Center and Dr. Markus Büchler of the University of Heidelberg, in a joint statement.
"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. However, the medical evacuation would have to take place as quickly as possible."
The doctors added that both their institutions have agreed and are prepared to accept Liu for cancer treatment.
Amid growing international concern over Liu's health, a Chinese vice minister of justice met with representatives from the US, German and EU embassies in late June to brief them about his case and told the diplomats that Liu was too sick to travel abroad, according to a source familiar with the meeting.
A few days after the meeting, however, the authorities said they had approved the family's request to invite Western doctors to join Liu's medical team, composed of prominent Chinese oncologists, at a hospital in Shenyang in northeastern China.
Herman and Büchler visited Liu on Saturday afternoon.
'The ball's in China's court'
A Chinese foreign ministry spokesman on Monday repeatedly declined to say if Beijing would allow Liu to leave the country.
"We hope relevant countries will respect China's judicial sovereignty and not use a so-called individual case to interfere in China's internal affairs," said Geng Shuang at a regular press briefing.
A statement released Saturday by the Shenyang hospital quoted the Western physicians as saying to Liu's Chinese doctors: "We have no better options -- you've already done a very good job," under the headline "American, German experts claim Liu has no better options abroad."
Liu, 61, was granted medical parole and released from jail last month after he was diagnosed with late-stage liver cancer. He had been serving an 11-year prison sentence for "inciting subversion of state power" in Jinzhou, near Shenyang.
His most recent conviction, on Christmas Day 2009, stemmed from his co-authorship of Charter 08, a manifesto calling for political reform and human rights in China.
In 2010, while in prison, Liu was awarded the Nobel Peace Prize for "his long and nonviolent struggle for fundamental human rights in China" -- prompting an infuriated Beijing to place his wife under house arrest and freeze diplomatic ties with Norway, where the prize winner is chosen.
Liu's plight has come under a global spotlight amid allegations from his supporters that he had become gravely ill because his cancer wasn't detected and treated in time in prison -- and that China has refused to let him seek treatment abroad for political reasons despite calls from other governments, including the US.
Some supporters say the latest development Sunday has cleared a major hurdle for Liu and his family to leave China.
"All he and his family need now are their passports -- as soon as China opens the gate, they can be on their way to true freedom," said Hu Jia, a leading Chinese human rights activist who has known Liu's wife for years and has served prison terms for his own advocacy.
"The ball's in China's court again," he added. "The doctors' words made it clear that there are no medical reasons for the government not to let him go."
Pressure on Chinese government
Earlier this month, 154 Nobel laureates across six disciplines signed and sent an open letter to Chinese President Xi Jinping, urging the Beijing authorities "on humanitarian grounds to grant Liu Xiaobo and (his wife) Liu Xia's wish to travel to the United States for medical treatment."
The Chinese government, which continues to censor domestic news coverage of Liu, has been waging a public relations offensive in the face of strong global reactions to the story.
The state-run Shenyang hospital has been steadily releasing more details on Liu's condition and treatment, revealing that his wife has been staying with him at the hospital and that traditional Chinese medicine (TCM) practitioners have joined the medical team at the family's request.
An earlier statement from Shenyang officials also quoted Liu's family as saying they were "satisfied" with his treatment in prison and at the hospital.
It added that Liu had a history of hepatitis B before imprisonment and prison authorities had provided him with an annual physical examination as well as monthly checkups, and no abnormal conditions had been found before the recent diagnosis.
A prolific writer and longtime activist, Liu has been in and out of jail since the bloody crackdown on pro-democracy protesters in Beijing's Tiananmen Square in 1989.