Amnesty International has called on the Chinese authorities to reveal the whereabouts of 20 ethnic Uighur asylum-seekers who were forcibly deported from Cambodia to China on 19 December 2009.
The group, which includes two very young children, may be at risk of torture or even execution since their forcible deportation at the request of the Chinese government.
Since 2001, Amnesty has documented cases in which Uighur asylum seekers or refugees who were forcibly returned to China were detained, reportedly tortured and in some cases, sentenced to death and executed.
"The 20 should either be charged with recognisably criminal offences or released," said Amnesty International's Asia-Pacific Director, Sam Zarifi, in a letter to the Chinese Foreign Minister, Yang Jiechi Buzhang.
"Their trials should meet international fair trial standards, and under no circumstances should the death penalty be imposed.
"Our concerns are heightened by the fact that the Chinese authorities have already executed nine people and sentenced eight others to death in relation to the July 2009 unrest in the Xinjiang Uighur Autonomous Region," said Sam Zarifi.
Amnesty International has also urged the Chinese government to provide the UN Refugee Agency (UNHCR) with immediate access to the 20 individuals to monitor their well-being.