Part the railway track was blown up early Sunday in the Dasht area, some 22km south of provincial capital Quetta, police official Mohammad Khan told AFP.

A patrol party found four home-made bombs attached to the track and called the bomb disposal squad but in the meantime one of the bombs went off, Khan said. No-one was hurt.

The track was immediately repaired and the incident caused no disruption to the train service, he added.

Separately, a rocket exploded at an electricity station located in the Quetta garrison, which suspended electricity supply to several parts of the city but caused no casualties, power company officials said.

A fire erupted after the blast, which was put out by local firefighters, they said.

Insurgents linked to certain ethnic Baluch chieftains have waged a two-year campaign to win more political rights and a greater share of profits from the region's vast natural resources.

They also oppose President Pervez Musharraf's plan to build several military cantonments in the province, which borders Afghanistan and Iran.