QUETTA - A bomb exploded on a road in the Pakistani town of Quetta on Monday, killing five people and wounding 17, police and a hospital official said.

Autonomy-seeking militants from the nationalist Baluch Liberation Army (BLA) were believed to be responsible, a police official said.

The BLA is fighting for control of gas resources in Baluchistan, Pakistan's largest but poorest province and its biggest source of natural gas. Quetta is the provincial capital.

"We received four dead bodies and 18 injured, while one child succumbed to his wounds in a ward," said Abdul Rahim, the senior doctor on duty at Quetta's main hospital, bringing the total number of dead so far to five.

Three of the wounded were in critical condition, he said.

"I was sitting outside my shop when a powerful explosion went off. It completely destroyed three shops," said Inayatullah, one of the wounded men, from his hospital bed.

No one has claimed responsibility for the bomb, which police said was planted on a bicycle left at a roadside near a hotel and a police station.

Senior provincial policeman Ghulam Mohammad Dogar said he suspected the bomb was the work of BLA militants, who have claimed responsibility for previous attacks in the area.

The militants say the people of Baluchistan receive little benefit from its natural gas. They have attacked gas facilities, blowing up pipelines, as well as railway lines, security checkpoints and other government targets.

Last month, the BLA claimed responsibility when five bombs exploded in a police training camp on the outskirts of Quetta, killing six policemen. The government declared the group a terrorist organisation in April.

The Baluch nationalist rebels have no links to al Qaeda- and Taleban-linked fighters based on the border with Afghanistan, security officials say.

The rebels have waged a low-key insurgency for decades but their campaign has intensified during the past year. Pakistan accused its old rival India of meddling in the province, which borders Afghanistan.

The government mounted a sweeping offensive in the 1970s aimed at finishing off the rebels.