Close associates outside of Tibet say Gyatso's health has worsened.

He suffers from a chronic lung condition and may not be receiving adequate medical treatment in prison, the human rights body said in a statement.

"Once again the Chinese government's wrongful imprisonment of a Tibetan risks becoming a death sentence," the statement quoted Sophie Richardson, China director at Human Rights Watch, as saying.

"Go Sherab Gyatso should be immediately released and given comprehensive medical care," he added.

Ministry of State Security agents detained Gyatso, 45, on October 26, 2020, in Chengdu, the capital of Sichuan province, the Chinese authorities said in an August 2021 statement, in response to an inquiry from three UN human rights experts, according to the HRW.

Tibetan sources outside the country report he was given a 10-year sentence and is in Chushul Prison, 20 km southwest of Lhasa.

The authorities transferred the monk to Lhasa where, on February 3, 2021, he was formally charged with “inciting secession”.

The government statement said he was later tried but did not give the date or outcome of the trial, the statement added.

The Chinese authorities had previously detained him on at least three other occasions.

He was on a routine visit to Chengdu for treatment of his medical condition in October 2020 when State Security agents seized him.

(With UNI inputs)