VOA bureau chief Bill Ide in Beijing contributed to this report.
Chinese authorities are refusing to discuss the sentencing of a dissident who stands to become the longest-serving Tibetan political prisoner, maintaining that details of his case are a "state secret."
Members of the Tibetan parliament in exile called international attention last month to the case of Lodoe Gyamtso, 57. Exiles say the man, also known as Sogkhar Lodoe Gyamtso, had already served a total of 23 years in prison for two previous convictions before receiving a new sentence of 18 years.
But when asked to confirm details of the sentence, an official at People's Middle Court in Nagchu prefecture, Tibetan Autonomous Region, declined.
"This is something that is a state secret," he told VOA. "Even if I knew about this case, I would not be able to tell you about it because this is something that is a state secret."
Tibetan exile groups say Lodoe Gyamtso was arrested after protesting in front of the Potala Palace in Lhasa on Jan. 28, 2018. On the same day, he released a video message through social media in which he declared he was starting a "campaign for world peace."
The exact date of the new sentencing is not known but came to light last month. His wife, Gakyi, was sentenced to two years, according to the exile groups.
Ngawang Tharpa, a member of the Tibetan parliament in exile who says Lodoe Gyamtso is his uncle, told VOA that he learned from two sources the verdict was handed down late last year, probably in October or November.
Ngawang Tharpa, who now lives in India, said he was told the latest sentence was for 18 years. Lodoe Gyamtso had previously been released in 2013 after serving 21 years in prison in Lhasa. In 2015 he was reportedly detained for two years for staging another protest.
A rights lawyer in China who spoke to VOA on condition he not be identified said he was aware of the case. He said a relative of Lodoe Gyamtso had contacted him in August or September of last year and talked about hiring him to represent the dissident, but had not followed through.
The lawyer said it was not unusual for the verdict to be announced only to the dissident and his family members or his lawyer.
"I think an 18-year sentence would be too much and quite a surprise to me," he said. "But I don't know why they didn't hire me to defend him. They might have been under heavy pressure."
Heavy sentences for dissidents in Tibetan areas are not uncommon, however. Lodoe Gyamtso's home area of Sog County is one of most restricted parts of the Tibetan Autonomous Region and phone lines are often blocked, according to Tibetans in exile.
VOA tried repeatedly to place phone calls to Sog County but received only a busy signal.