At least ten people, including six Chinese engineers and two Frontier Corps personnel, lost their lives and several others were injured on Wednesday following a bus explosion. The vehicle was carrying workmen to the Dasu Dam in the Upper Kohistan district of Khyber Pakhtunkhwa.

The cause of the explosion could not be ascertained and a rescue operation was underway. The site was cordoned off by police and Rangers, The Dawn reported citing Deputy Commissioner Arif Khan Yousafzai.

Yousafzai also informed that the incident took place early in the morning around 7:30 am when a coaster carrying over 30 workers from the Barseen camp to the plant site.

"At the moment we are not clear what exactly happened, whether it is a blast or an accident, once police will complete the initial investigation, the situation will become clear," a senior police officer told Dawn.com.

Meanwhile, the Water and Power Development Authority (WAPDA), confirmed that employees of a Chinese company were travelling in the bus, adding that rescue efforts were underway at the site of the incident and the injured were being shifted to a hospital.