Defying curfew, supporters of slain Baloch leader Nawab Akhtar Bugti on Monday rioted in Quetta and other cities of Pakistan's Balochistan province targeting government buildings, banks and business establishments.

At least three nationalist lawmakers, along with 600 protesters, were taken into custody as paramilitary forces lobbed teargas shells and fired in the air to control rioters.

A child was killed and eight persons were injured in the town of Pasni, southwest of provincial capital Quetta, reports said.

Shops, educational institutions and business establishments remained closed in all major cities of the province in response to a general strike called by local leaders.

A 79-year-old tribal chieftain, who had been leading a violent struggle against the central government over the region's natural resources, died along with several of his supporters after troops attacked his cave in Kohlu area, about 200 km east of Quetta, over the weekend. His body is yet to be recovered.

Rioters ransacked government offices, banks, a national airline office, a hotel and set ablaze several shops in Quetta, Gawadar and Pasni.

A mob torched the regional office of the government-run National Bank of Pakistan in Gawadar.

The Balochistan assembly session was aborted for the day and the legislature adjourned for several days following protests from opposition parties in the house.

Three nationalist lawmakers were arrested after they left the assembly building on charges of inciting shopkeepers to close for the strike.

A curfew was imposed on Quetta for an indefinite period from Sunday evening and heavy contingents of police and frontier corps personnel deployed in different areas.

Areas across Balochistan province, Sindh and Karachi, inhabited by large sections of Baloch people, were completely shut down.

"Police have arrested around 600 protesters in Quetta on charges of attacking government buildings and vehicles," reports quoted a senior police official as saying.

At least 45 vehicles, scores of shops, banks and government buildings were ransacked or set on fire.

While two bombs exploded in Kalat, a device planted in the building of Nadra went off, destroying its offices. A hand grenade was hurled into a telephone exchange.

The district offices of the ruling Pakistan Muslim League were set on fire in the coastal towns of Pasni and Gawadar.

Meanwhile, Bugti's relatives claimed that his grandsons, Nawabzada Baramdagh Bugti and Nawabzada Aali Bugti were alive and safe as they had left the area.

Another prominent Baloch leader, Nawabzada Balaach Khan Marri, was also alive, a spokesman for Anjuman Ittehad Marri said.

The government said Bugti's body would be handed over to his family as and when it was found from the rubble of the cave.

More protests were expected during the funeral of Bugti, who dominated Balochistan politics both as chief minister and governor as well as head of Jhambhoori Watan Party, which has shared power at the centre in the past.