BEIJING (REUTERS) - A blast in the capital of China's western region of Xinjiang killed 31 people, with around 90 others injured, state broadcaster China Central Television reported on Thursday.

The blast took place when two vehicles rammed into a crowd at a morning market in Urumqi. Explosives were hurled from the vehicles and one of the vehicles exploded.

President Xi Jinping pledged to severely punish terrorists and spare no efforts in maintaining stability, in response to Thursday's explosions in Urumqi, Xinhua reported.

China's domestic security chief has labelled the incident an act of violent terrorism. China has blamed a string of violent attacks in recent months on militant separatists from Xinjiang.