QUETTA, Pakistan (AP) — A roadside bomb exploded near a bus carrying security forces in restive southwestern Pakistan on Sunday, killing at least five officers and wounding 10 others, police said.

The attack occurred in Naushki, a district in Balochistan, said Zafar Zamanani, a local police chief. He said the the blast also badly damaged another nearby bus. The dead and wounded were transported to a nearby hospital.

Sarfraz Bugti, the chief minister of Balochistan, condemned the attack.

No one immediately claimed responsibility, but suspicion is likely to fall on the outlawed Baloch Liberation Army, which days ago ambushed a train, took about 400 people on board hostage and killed 26 hostages before security forces launched an operation and killed all the 33 attackers.

Oil- and mineral-rich Balochistan is Pakistan’s largest and least populated province. Ethnic Baloch residents have long accused the central government of discrimination — a charge Islamabad denies. Baloch Liberation Army has been demanding independence from the central government.