The health of the wife of China's jailed Nobel Peace Prize laureate has deteriorated under lengthy house arrest and she urgently requires medical treatment, close friends said Friday.

Liu Xia has been forcibly sequestered at home alone for the past three years by state security in apparent retaliation for the activism of her imprisoned husband Liu Xiaobo. In recent months, friends who have had contact with her family or her say she has been suffering from heart problems and depression.

Her condition took a turn for the worse last month when she suffered what felt like a heart attack and had to be rushed to a hospital's emergency ward for treatment, said Wu Wei, a close friend of Liu Xia.

Wu, a writer based in the southern city of Guangzhou, said Liu Xia told him in a brief phone call Friday that doctors say she suffers from a serious shortage of blood to the heart muscle. Wu, better known by his pen name Ye Du, also said Liu Xia had a cold and fever.

"She sounds weak," Wu said. "Because she's been kept indoors for long periods of time, she has few opportunities to exercise and strengthen her health."

Another family friend, a writer who spoke on condition of anonymity out of fear of government reprisal, confirmed Wu's account of Liu being rushed to hospital last month because of her heart. The writer added that Liu's family was considering asking for permission to send her abroad for medical treatment but that she worried she would not be allowed to return to China.

The couple's lawyer Mo Shaoping said Liu was admitted on Feb. 8 to a hospital in Beijing to undergo a battery of tests but was unexpectedly asked by the hospital to leave after one night.

Mo said Liu was accompanied by four or five police officers and that the hospital might have been intimidated by the security presence.

Liu Xia's brother-in-law, Liu Xiaoxuan, said he had spoken to her late last month and that she told him her heart was not well and that she was trying to see a doctor.

Her husband, Liu Xiaobo, was convicted of subversion in 2009 and sentenced to 11 years in prison after he wrote and disseminated the Charter '08 document calling for democracy. He was awarded the Nobel Peace Prize in 2010, an embarrassment for the Chinese government, which denounced the award.


Associated Press journalist Isolda Morillo contributed to this report.