PESHAWAR: Rescuers pulled survivors on Wednesday from a ravine after an explosion sent their bus over the edge, killing 13 passengers, among them nine Chinese nationals and two Pakistani soldiers, near the Dasu hydropower plant in the Upper Kohistan district of Khyber Pakhtunkhwa (KPK).
For several years, Chinese engineers and Pakistani construction workers have been working on hydroelectric projects as part of Beijing's Belt and Road Initiative in KPK, where the blast took place.
"The entire government machinery has been mobilised to rescue the injured by air ambulance," a senior government official told Reuters on condition of anonymity, adding that "heavy losses" resulted from the plunge into the ravine.
Beijing asks Pakistan to investigate bus blast that killed Chinese nationals
While Pakistan's foreign ministry blamed a mechanical failure for a "leakage of gas that caused a blast", China's foreign ministry decried the incident as a bomb attack that caused injuries and death to its nationals.
Nine Chinese were killed, the embassy in Pakistan said in a statement.
In Beijing, a foreign ministry spokesman offered condolences, urging the South Asian nation to thoroughly investigate the blast and protect the safety of Chinese personnel, institutions and projects.
A senior administrative officer of the Hazara region told Reuters the bus was carrying more than 30 Chinese engineers to the site of the Dasu dam in Upper Kohistan.
The Dasu hydroelectric project is part of the China-Pakistan Economic Corridor (CPEC), a $65-billion investment plan that aims to link western China to the southern Pakistani port of Gwadar.
The casualties, including the Chinese engineers, were taken to a hospital in Dasu, about 10 km (6 miles) from the blast site.
Dasu hydropower project to provide 1200bn units of electricity: PM
"Police and the bomb disposal squad are at the site," regional official Arif Khan Yousufzai told reporters outside the hospital, adding that authorities were waiting for an investigation report to ascertain details.
Initially, it had not been clear if the blast was caused by a device beside the road or planted in the bus.
"Looks like sabotage," the province's top police official, Inspector General Moazzam Jah Ansari, had told Reuters earlier. Police were investigating the incident whose casualties included two soldiers and two locals, as well as the injured, he added.
At least three other officials had confirmed to Reuters that a blast hit the bus.
Foreign Office expresses condolences over lives of Pakistanis, Chinese workers lost in bus accident
Pakistan's foreign ministry said it was in close contact with the Chinese embassy in the capital, Islamabad, adding in a statement, "Pakistan attaches great importance to the safety and security of Chinese nationals, projects and institutions."