BEIJING (Reuters) - The liver function of China’s Nobel Peace Prize winning dissident Liu Xiaobo has worsened, the hospital treating him said on Thursday, while one source close to his family said doctors had halted medication.

FILE PHOTO: A protester holds a portrait of Chinese Nobel rights activist Liu Xiaobo as she step on portraits of Chinese President Xi Jinping during a candlelight vigil demanding the release of Liu, ahead of 20th anniversary of the city's handover from British to Chinese rule, in Hong Kong, China June 29, 2017. REUTERS/Tyrone Siu/File Photo

Liu, 61, was jailed for 11 years in 2009 for “inciting subversion of state power” after he helped write a petition known as “Charter 08” calling for sweeping political reforms.

He was recently moved from jail to a hospital in the city of Shenyang for treatment of late stage liver cancer.

Liu has been being treated for various conditions as side effects of his cancer, including a build up of fluid in his stomach caused by liver scarring.

“Liu Xiaobo’s liver function has worsened, his bilirubin levels are gradually rising,” the hospital said in a statement, referring to a substance produced by the liver, high levels of which can indicate liver failure.

Asked about Liu’s condition on Thursday, Chinese foreign ministry spokesman Geng Shuang said he had nothing new to add and reiterated that China hoped other countries would not use “individual cases” to interfere in China’s internal affairs.

A liver expert from Beijing, Mao Yilei, had come to Shenyang to lead a consultation on Liu’s condition, the hospital said on Wednesday.

The team decided to adjust his treatment plan and the family said they understood, the hospital said on Wednesday, without providing details.

However, Ye Du, a dissident who is close to Liu’s family, said a source with direct knowledge of the situation said the team of doctors treating Liu had decided on Wednesday to halt medication after the deterioration in his condition.

“Liver function has worsened and it cannot take the medication, so Chinese and Western drugs to fight cancer have been halted,” the source told Ye in a message.

Reuters was unable to independently verify Ye’s assertion.

A message from more than 40 friends of Liu and his wife, Liu Xia, shared on instant messaging platforms called for friends to have access to the couple to provide support following the news of his deteriorating condition.

“From this moment, we urgently need the ability to visit, to bring Mr Liu Xiaobo and Mrs Liu Xia their friends’ care and well-wishes,” the friends said.

The Shenyang city justice department said on Wednesday the hospital had invited doctors from the United States and Germany to help with Liu’s treatment.

President Xi Jinping is due to attend a summit of the Group of 20 nations in Hamburg, Germany, on Friday and Saturday, where he will seek to project Chinese leadership on issues such as climate change and free trade.

Diplomatic sources in Beijing say China has been nervous the issue over the Nobel Peace Prize winner could overshadow Xi’s appearance.

Rights group Amnesty International said the invitation to foreign doctors appeared in part “an attempt to limit international criticism” even as the government continued to refuse to allow Liu to be treated overseas.