The violence in Urumqi, capital of northwest China's Xinjiang Uygur Autonomous Region, has left 140 people dead, the regional public security department said Monday.

Fifty-seven dead bodies were retrieved from Urumqi's streets and lanes, while all the others were confirmed dead at hospitals, said Liu Yaohua, the region's police chief, at a press conference midday Monday.

He said the death toll would still be climbing.

At least 828 people were injured in the deadly violence that erupted Sunday night.

Rioters burned 261 motor vehicles, including 190 buses, at least 10 taxis and two police cars, said Liu.

As of 9 am, several vehicles were still seen ablaze on Urumqi's streets he said.

A preliminary investigation showed 203 shops and 14 homes were destroyed in the riot.

Police have arrested several hundred in connection with the riot, including at least a dozen who were suspected of fanning the unrest, Liu said.

He said police are still searching for about 90 other key suspects in the city. "Police have tightened security in downtown Urumqi streets and at key institutions such as power and natural gas companies and TV stations to prevent large-scale riots."

Checkpoints have been set up in Urumqi's key areas as well the neighboring Changji and Turpan prefectures to prevent the rioters from fleeing, Liu said.

He said more than 100 ethnic officials from adjacent areas have been transferred to Urumqi for interrogating the suspects according to law.