"The United States condemns the horrific terrorist attack in Urumqi, China today. We are aware of reports that the attack resulted in the death of 31 citizens and the injury of 90 more," White House Press Secretary Jay Carney said.
"This is a despicable and outrageous act of violence against innocent civilians and the United States resolutely opposes all forms of terrorism," he said.
"We offer our condolences and sympathies to the victims, their families and all those affected by this attack," Carney said.
The blasts took place as two vehicles, without license plates, broke through roadside fences and ploughed into people at an open air market in Urumqi, provincial capital of the restive Xinjiang province, at 7:50 am (local time) and the occupants set off explosive devices.
Witnesses said explosives were thrown before the vehicles exploded.
Many of the injured were elderly people who frequently visited the morning market.