QUETTA, Pakistan (AP) -- A suicide bomber riding on a motorcycle rammed into a police truck in Pakistan's restive southwest, killing at least 10 policemen and wounding 12 officers in one of the deadliest attacks on security forces in recent months, authorities said.
No one immediately claimed responsibility for the bombing, which took place on a bridge in the district of Sibi in Baluchistan province, but Baluch separatists and local militants have been blamed for previous such attacks.
Mahmood Notenzai, a local police chief, said the officers were on a routine patrol when the attack happened, initially killing nine. The casualties were taken to a nearby hospital, where one of the critically wounded policemen later died, he added. Sibi is about 150 kilometers (90 miles) east of Quetta, the provincial capital.
The force of the blast overturned the truck, which caused additional injuries, he said. Trucks often transport troops in Pakistan.
Notenzai said the officers who came under attack were deployed last week to Sibi, where an annual cultural festival was held amid tight security. An army helicopter was sent to evacuate the seriously wounded to a hospital in Quetta, where better health facilities are available.
Last year, a suicide bomber from the extremist Islamic State group targeted President Arif Alvi 's security convoy when he attended the Sibi festival. Alvi was far away from the site of the bombing, which killed five troops. IS militants later claimed responsibility for that attack.
The festival has been celebrated for several centuries to mark the advent of summer.
Prime Minister Shahbaz Sharif condemned the attack. In a statement, he expressed his condolences to the families of those killed and ordered health officials to provide the best medical care for the wounded policemen. He said the attack was part of nefarious enemy plans to destabilize Pakistan and vowed to defeat terrorism.
Abdul Qudoos Bizenjo, the top elected official in Baluchistan, also denounced the bombing.
"The terrorists who are carrying out such attacks are the enemy of Pakistan," he said, adding that they will not shake the resolve of the country's police.
Baluchistan has long struggled with a low-level insurgency by the Baluchistan Liberation Army and other small separatist groups demanding independence from the central government in Islamabad.
Authorities claim to have quelled the insurgency but violence has persisted. The province has also seen attacks by militants from both the Pakistani Taliban and the Islamic State group.