After claiming Wednesday's bus blast in Dasu was the result of a mechanical failure, Pakistan said on Thursday they could not rule out terrorism as they had found traces of explosives. This was stated by information minister Fawad Chaudhry in a tweet in which he also added the "govt is in close coordination with Chinese embassy we are committed to fight menace of terrorism together."

His statement came a day after Foreign Minister Shah Mahmood Qureshi told his Chinese counterpart Wang Yi that Pakistan did not think it was a terrorism related incident but a mechanical fault in the bus that resulted in it crashing into a ravine and killing 13 people.

Yi called on Pakistan to find and arrest the perpetrators.

Chinese ambassador visits site

China's Ambassador to Pakistan Nong Rong on Thursday visited the blast site according to Reuters.

Arriving at the blast site, Nong was briefed by the Pakistan military and inquired information. A police counselor from the Chinese Embassy went down to the bottom of the canyon, which is about 30 meters deep, to check an overturned bus.

According to staff from the Dasu Hydropower Project, the blast took place at 07:04 on Wednesday, and the vehicles were just about one kilometer away from their camp and about eight to ten kilometers away from the construction site.

Rescue started about 16 minutes after the blast.

"Yesterday, up to 100 people from our project took part in the rescue, and the Pakistan side sent at least 200 people. There were a lot of Pakistani people, and they were united, giving us great help. At least 200 people were here for rescue," said Cui Jian, executive deputy manager of the Dasu Hydropower Project from China Gezhouba (Group) Corporation.

After visiting the blast site, the ambassador arrived at the camp for the Dasu Hydropower Project and was briefed by local police.