She thanked "all those people that have supported Liu Xiaobo" and "strongly asked" the Chinese government to release the dissident, who died a year ago of liver cancer while on medical parole from an 11-year sentence for "subversion".
"Liu Xia is finally free and today the world celebrates her enjoyment of the liberties that were rightfully hers all along", he said.
BBC Chinese, citing unnamed sources, said Liu had left Beijing on a Finnair flight to Germany on Tuesday at around 11am local time.
Liu, a petite, bespectacled poet, was photographed smiling as she entered the terminal in a gray T-shirt under a black and white knit cardigan.
"While Liu Xia is free, our work is not complete", he said.
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And the Liverpool defender cheekily said that it has something to do with the parents across the country. If England advance to the final they will face France on Sunday at 5pm. "That speaks volumes in itself".
Her departure, following a year of pressure on Beijing from activists and rights groups, comes at the end of a visit to Germany by Chinese Premier Li Keqiang, during which the two countries signed commercial deals worth more than $23 billion.
Liu Xia's departure was "wonderful news" but harassment of her family remained a risk to her freedom to criticise China, Amnesty International's China researcher Patrick Poon said.
German Chancellor Angela Merkel has been vocal about Chinese human rights abuses and is believed to have pushed for Liu Xia's release during her May visit to Beijing, where she met the wives of detained human rights lawyers.
China sentenced Liu Xiaobo in 2009 to 11 years' imprisonment on charges of inciting subversion of state power.
Chinese Foreign Ministry spokeswoman Hua Chunying confirmed Liu Xia's departure on Tuesday, telling a press briefing that the widow left for Germany of her own accord to receive treatment.
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The four boys rescued Sunday can eat normal food and walk around, and the four pulled out Monday were eating soft food. It could be at least seven days before they can be released from the hospital, Jedsada told a news conference.
She departed Beijing overnight and is traveling to Berlin, according to her attorney, Jared Genser, who credited President Trump, German Chancellor Angela Merkel, "and so many others in the worldwide community who helped make today possible".
"I'm in a sea of joy", said veteran activist "Long Hair" Leung Kwok-hung as he drank a toast to Liu Xiaobo.
The poet and artist was reported to be suffering from heart problems and severe depression in December 2013, but was reluctant to seek medical attention because she feared further punishment.
Following Liu Xiaobo's release on medical parole last June, the dissident requested permission to receive treatment overseas - an unfulfilled wish that friends believed was for Liu Xia's sake. It also comes nearly one year after the death of dissident Liu Xiaobo. He returned from an academic job in the United States to take part in the 1989 demonstrations in Tiananmen Square and was arrested in the aftermath of the massacre there - the first of several stints in Chinese jail cells.
Despite a diagnosis of late stage liver cancer and calls from the global community to release him for urgent medical treatment, Liu Xiaobo died at the age of 61 while still imprisoned on July 13, 2017. Chinese officials told reporters Liu Xia was free to do what she wished, but authorities banned Western diplomats from visiting her. The last time a famous political prisoner was permitted to leave China was in 2012. Nineteen measures were itemized with the aim of improving China's human rights situation. "Dying is easier than living - there is nothing simpler for me than to protest with death". He also has introduced a bill to rename the street in front of the Chinese embassy in Washington "Liu Xiaobo Plaza".
Diplomats have said that authorities continued to monitor Liu Xia after the death of her husband and she had only been able to meet and speak to friends and family in pre-arranged phone calls and visits.
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The rising hope only makes the dip of despair even more chastening. "No way will they have such an easy route next time". And then, just when England thought old fears could be dismissed and new chapters of success written, it happened again.