A bomb planted in a rickshaw tore through a truck used by security forces in southwest Pakistan on Thursday, killing at least 13 people, police said.

The remotely detonated bomb containing around 100 kg (220 pounds) of explosives targeted a truck carrying members of a government paramilitary force on the outskirts of Quetta, the capital of restive Baluchistan province.

Baluchistan, Pakistan's largest but most undeveloped province, is racked by Islamist and sectarian violence as well as a long-running separatist insurgency, and attacks on security forces are common.

"At least 13 people have been killed, 12 of them were security personnel," senior police official Fayyaz Sumbal told AFP.

"The bomb was planted in a rickshaw (tricycle). The target was a truck of Baluchistan Constabulary which was carrying the security personnel."

A further 11 people were wounded in the attack, he said. There was no immediate claim of responsibility.

Television footage showed the burnt-out remains of the rickshaw and truck almost completely destroyed by the blast in an open area on the edge of the dusty, low-rise city.

Bomb disposal officer Abdul Raazaq confirmed the incident and the size of the bomb.

Baluchistan, which borders Afghanistan and Iran, has significant reserves of gas and other resources, but development has been limited by the volatile security situation.

Ten days ago the provincial police chief narrowly escaped a suicide car bomb attack outside his home in Quetta. The blast killed at least six people and wounded 46 others.

Thursday's attack came on the second day of a visit by Chinese Premier Li Keqiang, who pledged to link Pakistan and China in an "economic corridor".

In February China took over control of the Arabian Sea port of Gwadar in the southwestern corner of Baluchistan, which could give Beijing easier access to Gulf oil if security in the province improves.

The Pakistan Muslim League-N (PML-N) party of incoming prime minister Nawaz Sharif looks set to form a coalition government in the Baluchistan provincial assembly following a general election on May 11.

Hopes were voiced last week that a coalition between PML-N and nationalist parties could assuage some of the long-held grievances in the province about its treatment by the federal government.