PESHAWAR: Government ramped up security guarding Chinese engineers building Beijing-linked projects in the nation’s northwest, an official said Wednesday, a day after five workers were killed in a suicide bombing.

Beijing is Islamabad’s closest regional ally and Pakistan has benefitted from billions of dollars of investment in recent years, but has struggled to guarantee the safety of Chinese migrant workers.

The five Chinese engineers — plus their Pakistani driver — were killed while travelling between Islamabad and a hydroelectric dam construction site in Dasu, in northwestern Khyber Pakhtunkhwa province.

A high-ranking official from the provincial interior ministry told AFP on Wednesday that at the more than two-dozen sites hosting Chinese engineers in Khyber Pakhtunkhwa security was stepped up.

“Directives have been issued to all law enforcement agencies to enhance security for Chinese nationals and all other foreigners,” he said on condition of anonymity.

“Instructions have also been given to foreign nationals to restrict their movements.”

Information minister Attaullah Tarar told a press conference in Islamabad that security procedures would be reviewed “with a focus on identifying and addressing any gaps”.

Meanwhile, further details emerged about the attack, which has yet to be claimed by any militant group.

Local police officer Bakht Zahir said the five engineers killed near the city of Besham included four men and a woman, and that the bomber targeted the middle vehicle in a convoy of 12.

“The suicide bomber rammed his vehicle into the convoy in the middle, detonating himself, causing the Chinese engineers’ vehicle to fall into a 180-foot-deep (55-metre) ravine and catch fire,” he said.