Liu Xia, the widow of the late Nobel Peace laureate Liu Xiaobo, left Beijing on Tuesday and was on her way to Berlin, after years of unofficial house arrest on the mainland.
Her friend and activist Ye Du said Liu Xia had boarded a Finnair flight to Europe, although her brother, Liu Hui, was still in Beijing.
Liu Hui soon corroborated the news with a posting on social media and several hours later, the foreign ministry confirmed that Liu Xia had departed for Germany, saying she was going there for medical treatment
Liu Xia, a poet, was put under house arrest in 2010 shortly after her husband was detained on subversion charges. He died in custody in July 2017, just weeks after the authorities said he had been diagnosed with terminal liver cancer.
Liu Xia, who has never been accused of any crime, was reported to have been suffering from depression. In May, one of her friends, Liao Yiwu, quoted her as saying "dying is easier than staying alive" since her husband's death.
Liao released a recording of a telephone conversation with Liu Xia where they discussed her wish to leave China and go to Germany.
Berlin stated publicly that it would welcome Liu Xia and said it had been discussing her case with Beijing and would continue to do so.
Her departure from China came as Premier Li Keqiang was on a visit to Germany. He had held talks with Chancellor Angela Merkel on Monday.
Liu Xiaobo was jailed on subversion charges for co-writing Charter 08, which advocated freedom of association, an independent legal system and an end to one-party rule on the mainland.
He was awarded the Nobel Peace Prize in 2010, and was represented at the ceremony in Oslo by an empty chair.
Since his death, pro-democracy campaigners in Hong Kong have held repeated protests demanding Liu Xia's release from house arrest.
Last updated: 2018-07-10 HKT 15:24