Four people were killed and 15 others injured in a bombing that targeted the vehicle of a police superintendent in a marketplace in the southwestern Pakistani city of Quetta on April 10, the city's police chief said.

Two policemen were among the dead in the attack in Kandahari Bazaar, police chief Zohaib Mohsin told reporters in Quetta, capital of Pakistan's restive Balochistan Province.

The explosion also damaged nearby cars and motorcycles, Mohsin said. There have been no arrests in the attack, which comes nine days after Pakistan said four of its soldiers were killed along the province's border with Iran.

Senior police official Shafqat Cheema said earlier that the target was the vehicle of the acting superintendent of police investigations.

The outlawed Baluch Liberation Army (BLA) claimed responsibility for the attack, saying its fighters used an improvised explosive device (IED) to attack the car of Superintendent Naseer-ul-Hassan Shah in the bazaar, which is one of the busiest markets in Quetta. It was unclear whether Shah was among the victims.

"Two policemen were killed, several were injured, and the vehicle was badly damaged in the attack," BLA spokesman Jeeyand Baloch said in a statement.

The spokesman said the BLA targeted the superintendent because it claimed, without providing evidence, that he had been involved in the "inhumane treatment of Baluch civilians under the pretext of investigations."

The BLA, which has been designated as a terrorist organization by Pakistan, the United States, and Britain, routinely takes credit for attacks on Pakistani security forces. Officials in Islamabad say the group has set up sanctuaries in border areas of Iran. Tehran denies this.

The BLA claims to be fighting for the independence of Balochistan, a sparsely populated province rich in natural resources such as copper, gold, and gas. The insurgent group claims ethnic Baluchi face extortion and discrimination by Pakistani authorities. Islamabad rejects the charges.

Ethnic Baluchis account for just under 4 percent of Pakistan’s population of 231 million.

With reporting by Reuters