NINE Chinese workers were among 13 people killed on Wednesday (14) when a blast on a bus sent it careening down a ravine in northwestern Pakistan, government and police officials said.
Pakistan's foreign ministry in a statement said the bus plunged into the ravine after “a mechanical failure, resulting in leakage of gas that caused a blast".
China's foreign ministry spokesman Zhao Lijian expressed his "shock and condemnation over the bombing". He urged Pakistan to "severely punish" those responsible and "earnestly protect" Chinese nationals and projects.
The bus was carrying 40 Chinese engineers, surveyors and mechanics to the Dasu dam construction site in the Khyber Pakhtunkhwa province, a local government official who did not want to be named said.
"The blast sparked a fire in the engine, plunging the vehicle into a ravine," he said.
He said 28 Chinese nationals were injured.
The security of Chinese workers has long been an issue of concern in Pakistan. Large numbers of them are based in the country to supervise and build infrastructure projects.
In a statement on Wednesday (14), the Chinese embassy said that "a certain project of a Chinese firm in Pakistan suffered an attack, which caused the deaths of Chinese nationals".
It urged Chinese firms to strengthen their security procedures.
Beijing has poured billions of dollars into Pakistan in recent years to boost the country's infrastructure.
But Chinese-funded projects have sparked resentment, particularly among separatist groups, who say locals see little benefit, with most jobs going to outsiders.
Construction of the Dasu dam on the Indus River began in 2017 and was scheduled to be completed within five years, according to the Pakistan Water and Power Development Authority.
The Dasu hydroelectric project is part of the China-Pakistan Economic Corridor (CPEC), a $65 billion (£46.8b) investment plan under Beijing's Belt and Road Initiative that is aimed at connecting western China to the Gwadar seaport in southern Pakistan.
Chinese engineers and Pakistani construction workers have been working on the Dasu hydroelectric project and several others for several years in the region where the blast took place.
Rishi Sunak and Akshata Murty. (Photo by HENRY NICHOLLS/AFP via Getty Images) 
