Witnesses said two cross-country vehicles driving from north to south ploughed into people in the market at 7:50 a.m and explosives were thrown out of the cars, one of which exploded, state-run Xinhua news agency reported. It said unknown number of people were killed and injured.
Injured were rushed to different hospitals, police said. A businessman in the market said he heard a dozen of big bangs. The open air morning market is located near the Renmin Park in downtown Urumqi. Ambulance and police cars parked at the entrance of Park North Street leading to the market helped evacuate the injured.
Flames and heavy smoke were seen nearby while the area had been cordoned off after the blast. Xinjiang, bordering Pakistan-occupied Kashmir and Afghanistan, has been plagued by violence for years. The region has witnessed riots between native Muslim Uygurs and Han settlers from outside the province.
Uygurs, a Turkic speaking community, resent the settlements as they believe the large scale migration is marginalising them in their own homeland. China accuses the East Turkistan Islamic Movement, an al-Qaeda affiliate, responsible for the large scale violence in and outside Xinjiang. Last month Xinjiang was the scene of a railways station attack which killed three and injured 79 people. The attack was blamed on radical religious extremists seeking to take control of the region.