Five Chinese workers and their local driver were killed in a suicide bomb blast in northwest Pakistan on Tuesday, authorities said, the latest in a string of terror attacks that the South Asian country’s military and government say aims to disrupt Islamabad’s close ties with Beijing.

Senior police official Muhammad Ali Gandapur said the explosion occurred when the bomber rammed a vehicle into the workers’ convoy as it traveled from the capital to the Dasu dam, the country’s largest hydropower project, in Khyber Pakhtunkhwa province.

The blast is the third atrocity in a week to rock Pakistan, a strategic ally of China and a key link in Chinese leader Xi Jinping’s ambitious Belt and Road infrastructure initiative, underscoring the mounting security challenges for Chinese projects in the country.

No group claimed responsibility for Tuesday’s blast, which comes nearly three years after a bus explosion killed 13 people including nine Chinese workers on their way to the dam in another unclaimed attack on the project.

Pakistan has been grappling with a surge in violence from militant and terrorist groups since the Taliban seized power in neighboring Afghanistan following the withdrawal of American troops in 2021. The Pakistani Taliban denied any involvement in Tuesday’s blast.