(Quetta) At least four people were killed and 15 injured on Monday in a bomb blast targeting a police vehicle in southwestern Pakistan, local police said.

The explosion took place in a busy market in Quetta, the capital of Balochistan province, where local separatist groups and armed Islamist movements regularly carry out attacks targeting the army or the police.

“Preliminary investigations suggest that an explosion was caused by an improvised explosive device that had been placed on a motorbike and was detonated remotely,” senior local police officer Azfar Mehsar told AFP.

At least four people, “two policemen and two civilians” were killed in the blast, he said.

Wasim Baig, a spokesman for Sandeman Hospital, the largest in Quetta, confirmed the toll, saying a five-year-old girl was among the dead.

The attack was not immediately claimed.

Balochistan, Pakistan’s largest, least populated and poorest province, which borders Iran and Afghanistan, has been rocked intermittently for decades by a separatist rebellion.

Jihadist groups, such as the Tehreek-e-Taliban Pakistan (TTP), the Pakistani Taliban, also operate there.

The province is rich in hydrocarbons and minerals, but its population – around 12 million people – complains of being marginalized and dispossessed of its natural resources.

In Balochistan, major construction sites of the China-Pakistan Economic Corridor (CPEC), an infrastructure project for which China is to spend more than 50 billion dollars, have emerged from the ground, including its flagship, the deep water port from Gwadar.

These Chinese projects have often created strong resentment in the province, especially with separatist groups who believe that the local population does not benefit from them, with most jobs going to Chinese workers.