According to the paper police have not said how many of those initially detained have been charged or released so far.
On Thursday police in Urumqi issued photographs of 15 suspects expected to stand trial with promises of leniency for others who turned themselves in.
Those who did not, they said, would be "punished severely".
Officials said nearly 200 people were killed and more than 1,700 injured during the unrest, but Uighur leaders in exile say about 10,000 people have either gone missing, detained or killed since then.
|Australia said there was no evidence to show Rebiya Kadeer was a terrorist [Reuters]
In a separate development, Australia's foreign minister has dismissed Chinese objections to a visit by Rebiya Kadeer, an exiled Uighur leader, saying there is no reason to stop her coming as she is not a "terrorist".
The Chinese government blames Kadeer, the Washington-based head of the World Uighur Congress, for instigating the ethnic unrest in Xinjiang last month.
Stephen Smith, the Australian foreign minister, said Kadeer has been given a visa for next week's visit because there "no evidence or information that she's a terrorist".
"This will be, I think, her third private visit," he told Australia's Sky News late on Thursday.
Kadeer will be attending the Melbourne International Film Festival to launch the documentary 10 Conditions of Love about her life and meet members of Australia's Uighur community.
The Chinese embassy in Canberra in complaining about her visit said "Rebiya Kadeer is a criminal", according to The Australian newspaper.
"Facts have indicated that the violent crime on July 5 in Urumqi was instigated, masterminded and directed by the World Uighur Congress headed by Rebiya."
Smith said he had no plans to meet Kadeer and declined to join her call for a UN investigation into the ethnic clashes, and insisted that relations with China, Australia's key trading partner, would not be affected.
The mainly Muslim Uighurs, China's sixth largest ethnic minority, say last month's unrest was touched off when armed police moved in to disperse a peaceful protest in Urumqi called after two Uighur workers were killed in a clash with Han Chinese during a brawl at a toy factory in southern China in June.
The Xinjiang region has long been a hotbed of ethnic tension, fostered by a growing economic gap between Uighurs and the Han Chinese, government curbs on religion and culture, as well as a massive influx of Han migrants who are now the majority in Urumqi.