The attack took place on a bridge in Balochistan’s Sibi district which is about 150km east of provincial capital Quetta.
No group has claimed responsibility for the attack yet.
Officers were on a routine patrol when the attack took place, Mahmood Notenzai, a local police chief, was quoted as saying to the Associated Press.
While nine people were initially said to be killed, more casualties were reported after the injured were taken to hospital.
The force of the blast overturned the truck, which caused additional injuries, Mr Notenzai said.
He added that the officers who came under attack were deployed last week to Sibi, where an annual cultural festival is 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.
Sunday’s attack comes a year after an Isis suicide bomber targeted Pakistan president Arif Alvi’s security convoy when he attended the Sibi festival.
While the president was far away from the site, five troops had been killed.
The festival has been celebrated for several centuries to mark the advent of summer.
Pakistan’s Balochistan has seen insurgency movements by the Balochistan Liberation Army and other small separatist groups demanding independence from the federal government.
While authorities claim to have quelled the insurgency, violence has persisted.
The area has also seen attacks by militants from both the Tehreek-e-Taliban Pakistan (TTP) and Isis.
“The terrorists who are carrying out such attacks are the enemy of Pakistan,” Abdul Qudoos Bizenjo, the top elected official in Balochistan, said after Monday’s incident.
Prime minister Shehbaz Sharif also blamed Pakistan’s enemies, without elaborating, and an alleged bid by them to destabilise the country.
He vowed to defeat terrorism while condoling the deaths and directed health officials to provide the best medical care to the injured officers.
Last month, the TTP claimed responsibility for a bombing near a vehicle carrying paramilitary troops in Balochistan, an attack that killed a soldier and injured 11 people, mostly civilians, police and security officials.
The group was also responsible for the deadly attack on a mosque in Peshawar in January in which over a 100 people were killed in a suicide bombing.
Additional reporting by agencies