QUETTA, Pakistan — A suicide bomber detonated his explosives vest in the southwestern city of Quetta, killing at least four people and wounding 19 others, police said Saturday.

Senior officer Abdur Razzaq Cheema said the suicide attack took place near a bus terminal in the city’s outskirts. The target was the vehicle of an army colonel but the officer was not in the vehicle at the time of attack, he said.

Cheema said most of the victims were civilians, including a child, while four security men were also wounded.

Explosive experts concluded that some 10 kilograms (22 pounds) of explosives with steel balls were used in the suicide vest, Cheema said.

Pakistan’s Taliban group claimed responsibility for the suicide attack, which came two weeks after a suicide bomber killed Quetta’s police chief and three other officers. The Pakistani Taliban also claimed responsibility for that attack.

Quetta is the capital of Baluchistan province, the scene of a low-level insurgency by Baluch separatist groups. Islamic militants also operate in the region.

Meanwhile, the Islamic state group has claimed responsibility for killing a senior police officer and his guard in a suicide attack in the northwestern city of Peshawar on Friday.