Chinese security forces launched a massive security crackdown in Xinjiang in early July, following riots in Urumqi by the region's indigenous Uighur minority.
"Disappearing' people is not the behaviour of countries aspiring to global leadership"
Human Rights Watch
During the clashes, many ethnic Han Chinese – China's dominant ethnic group – were attacked.
According to the government nearly 200 people died – most of them ethnic Han - in what was China's worst outbreak of ethnic unrest in decades.
In its report, entitled "We Are Afraid to Even Look for Them", HRW quoted Uighur residents in Urumqi describing how security forces raided several neighbourhoods following the riots.
The witnesses told the group that in several cases police had hauled away male residents who either had wounds or were not at home during street protests.
"They told everybody to get out of the houses. Women and elderly were told to stand aside, and all men, 12 to 45 years old, were lined up against the wall," a resident identified as Aysanam was quoted as saying.
|Some Uighur families said they have had no word on the fate of their relatives [EPA]
"Some men were pushed on their knees, with hands tied around wooden sticks behind their backs; others were forced on the ground with hands on their heads," she said.
In another incident, the report said soldiers had snatched a 14-year-old boy named Sharafutdin from the street. He has not been seen since.
HRW said the boy's father has asked at the local police station five times as to the whereabouts of his son, only to be told Sharafutdin was not on their list of detainees.
Commenting on the findings, Brad Adams, HRW's Asia director, called on the international community to press China for "clear answers about what
happened to those who have disappeared," saying trade issues and other concerns should not mean China is treated any differently.
'Dead or alive'
"The Chinese government says it respects the rule of law, but nothing could undermine this claim more than taking people from their homes or off the street and 'disappearing' them – leaving their families unsure whether they are dead or alive."
He added: "'Disappearing' people is not the behaviour of countries aspiring to global leadership."
While condemning the reported disappearances, the HRW report also criticised Uighurs who had led attacks on members of the Han community during the unrest.
It said that while the July 5 demonstration was initially peaceful, the protest had later descended into an attack on Han Chinese in the city.
China has sentenced 12 people to death over the July violence, with hundreds more thought to remain in custody.