Traces of explosives detected in Pakistan bus blast

Pakistan said on Thursday traces of explosives had been detected during an initial investigation into a bus blast that killed 13 people, including nine Chinese workers, and said a terrorist attack could not be ruled out as the cause of the incident.

Wednesday's blast in northwest Pakistan sent the bus hurtling over a ravine. China said it would send a team to help investigate.

Pakistan originally blamed a mechanical failure, but on Thursday Information Minister Fawad Chaudhry tweeted: "Initial investigations ... have now confirmed traces of explosives. Terrorism cannot be ruled out."

The Chinese workers were employed at the Dasu hydroelectric project, part of the China-Pakistan Economic Corridor, a US$65 billion investment plan aiming to link western China to the southern Pakistani port of Gwadar.

Chaudhry said Pakistani Prime Minister Imran Khan was personally supervising all developments in the matter.

"In this regard government is in close coordination with Chinese embassy, we are committed to fight menace of terrorism together," Chaudhry added in his tweet.

Senior Chinese diplomat Wang Yi met Pakistani Foreign Minister Shah Mahmood Qureshi on Wednesday and urged Pakistan to investigate the blast.

Wang told Qureshi that if it was indeed an attack, Pakistan should immediately arrest the culprits and punish them severely.

Wang, who is China's State Councillor and foreign minister, said "lessons should be learned" and both sides should strengthen security measures for China-Pakistan cooperation projects.