BEIJING, Jan 20: Fourteen people were killed and 13 injured in two explosions on Thursday in northwest China's Xinjiang region.

The first blast happened at 1:30pm (0530 GMT) when a bus travelling from the Dushanzi district of Karamay city to Usu city in northern Xinjiang exploded on a highway and killed 12 people, Xinhua news agency and officials said.

A police officer in Kuitun, the nearest city to the blast, said the cause was still under investigation but it did not appear to be a traffic accident.

"It's definitely not a regular accident," the official, who declined to be named, told AFP. "The provincial police department have sent people here."

Local authorities said it was not immediately clear whether separatists may have carried out an attack on the bus. The Kuitun officer, however, added: "We're at the frontline of anti-terrorism."

Eight of the victims were killed instantly while four died in hospital, Xinhua said. Two more were injured.

Most of the victims were ethnic minorities and not Han Chinese, said an official at the Kuitun city Prefecture Hospital. "We're still trying to save the injured," said the official.

Asked whether separatists may have caused the bus blast, a woman surnamed Chen at the Xinjiang provincial public security department said it was "hard to say."

"In the short-term, it won't be clear," Chen said.

About four hours later, a natural gas leak caused a blast that killed two people and injured 11 in the centre of Xinjiang's capital Urumqi, Xinhua said. The blast left a nine square meter hole in the ground, it quoted a Urumqi official as saying.-AFP