The Office of the United Nations Human Rights Commissioner has expressed alarm following the 10 year jail sentence imposed in China on a veteran activist, Chen Xi, who was involved in the 1989 protests in Tiananmen Square.
Chen Xi was convicted of subverting state power after a trial lasting a few hours. He had published essays online criticising the Communist Party.
The jailing comes days after another activist, Chen Wei, was imprisoned for nine years for the same offence.
Rights groups expressed outrage and accused Beijing of using the Christmas period as cover for a crackdown.
Human Rights Watch spokesperson Nicholas Bequelin said it worked well because there was no diplomatic activity around Christmas.
"By the time the diplomats get back to their desks, the sequence of events has moved on", he said.
Chen Xi's wife, Zhang Qunxuan, told reporters that her husband was innocent, but would not launch a "futile" appeal against his conviction.
"Chen Xi told the court it did not take into consideration the things he has written as a whole, and has interpreted his words out of context. But they have power and they don't listen," she said.