"Miscreants detonated a bomb that blew up a pipeline and disrupted gas supplies to thousands of homes in Mastung and Qalat districts," local police officer Hamid Shakil said.

The blast took place 35km south of the provincial capital Quetta, amid calls by opposition parties to stage demonstrations across Baluchistan over the August 26 killing of veteran Baluch leader Nawab Akbar Bugti.

Bugti, who died in a cave-hideout during an army operation, was buried in haste on Friday, hours after his decomposed body was retrieved from the collapsed cave.

His death sparked nationwide protests and deadly violence in Baluchistan where 10 people died in bomb blasts, attacks and clashes with the police in the past week.

Rallies were held on Sunday in the towns of Turbat, Pasni and Khuzdar but no incidents were reported.

Security was tight in Quetta where a multi-party alliance was to hold a separate rally later in the evening.

Police and paramilitary troops were deployed at government buildings and key intersections in the city, witnesses said.

The rallies were against the killing of Bugti and the refusal to hand over the body to his family, nationalist leader Akhtar Mengal said.