Dozens of men from the Uighur ethnic group remain unaccounted for after being detained in police sweeps three months ago during deadly ethnic rioting in China's far west, a human rights group said Wednesday.

New York-based Human Rights Watch said the 43 missing men and teenagers were among hundreds rounded up by security forces in the days and weeks following the July 5 riots in Urumqi city and their families have been unable to find out where they are or why they are being held.

The rioting left nearly 200 people dead as the mainly Muslim Uighurs attacked people from the Han Chinese majority, and was the deadliest communal violence in at least a decade in Xinjiang, the oil-rich region that abuts Pakistan and Central Asia.

In its wake, the government has smothered Urumqi, the regional capital, and much of Xinjiang with security but has failed to restore calm or ease ethnic tensions. More protests broke out in September, this time by Hans.

The Human Rights Watch report appears to be "a sober and even conservative documentation of the disappearances that have devastated Urumqi's Uighur community," said Rian Thum, a Uighur history researcher at Harvard University.

The disappearances add to "a long list of Uighur grievances and have only deepened the sense of injustice that most Uighurs share," Thum said in an email.

Report based on interviews

Human Rights Watch said its report is based on dozens of random interviews with Han and Uighur people living in Urumqi in the months after the riots. Victims and their family members are not identified by their real names for their protection and exact interview dates are also withheld.

One woman is quoted as saying her 14-year-old brother was taken away by soldiers on Aug. 7 and police have denied holding him. Most of the cases involve men in their 20s who were allegedly taken from their homes in early July, shortly after the riot.

"The actual number of 'disappeared' persons is likely significantly higher," the report said. "Our ability to collect information was limited. Out of fear of retaliation, few witnesses or family members were willing to come forward with their stories."

The Xinjiang government did not immediately respond to requests for comment on the report. A spokeswoman, Hou Hanmin, said she would look into the report's allegations.

Details of the police crackdown have been scant and conflicting. Police initially reported more than 1,400 people were arrested, then earlier this month said that only 825 were detained so far.

The official China Daily newspaper cited a deputy chief prosecutor in Urumqi this month as saying hundreds of cases are still pending and 145 detainees have yet to be formally charged. So far, 21 people have been convicted after trials, with nine sentenced to death.

The Uighurs see Xinjiang as their homeland and resent the millions of Han Chinese who have poured into the region in recent decades. A simmering separatist campaign has occasionally boiled over into violence in the past 20 years.

Incitement alleged

While arrests from the rioting remain murky, the government has renewed an effort to accuse Uighur activist groups in exile for inciting the riot.

A 20-minute documentary by China Central Television's news channel that aired last week and has been posted online claims overseas activists used chat rooms, websites, fake news and fake video to fan Uighur anger against Han Chinese in the days and weeks before the riot.

The film accused Dilxat Raxit, a spokesman for the German-based World Uyghur Congress, of passing off a video of a Kurdish teenager being beaten to death in Iraq as footage allegedly showing Han Chinese men killing a young Uighur woman.

He denied the claim during a telephone interview with The Associated Press on Tuesday.