The shadowy Baluchistan Liberation Army said it would strike the oil and gas installation at Dhodak in the central Pakistani province of Punjab.
It marks an apparent attempt by the group to spread violence to other areas beyond the southwestern province of Baluchistan, where it was blamed for an attack on a gas plant last month which killed eight people.
"We will blow up the oil and gasfield in Dhodak if non-locals working at the plant are not expelled," the group's purported spokesman Azad Baluch - an apparent nom de guerre meaning Free Baluchistan - said.
Oil pipe attacked
Baluch issued the warning in a telephone call to local newspaper offices on Sunday at the same time as he claimed responsibility for a blast which ruptured a gas pipeline, also in Punjab.
The explosion on Saturday near Mangrotha in Dera Ghazi Khan district, 90km west of the central city of Multan, disrupted gas supplies to some places in the populous Punjab.
Baluchistan is the biggest and
poorest province in Pakistan
Local officials said they had taken steps to protect national assets, including the Pakistan Atomic Energy Commission facility at Dera Ghazi Khan, 112km east of Dhodak.
"We have made all necessary arrangements for the security of sensitive areas like Dhodak gasfield, atomic energy station, bridges and railway track in Dera Ghazi Khan district," district police chief Salman Chaudhry told AFP.
Chaudhry said police and paramilitary troops patrolling in the area were "keeping a vigilant eye on suspects".
"We take notice of all threats or warnings given by terrorists and we are taking the Baluchistan Liberation Army's threat seriously."
Bombs targetting railway tracks - including the main line to Iran - or government installations have been exploding almost daily in Baluchistan, the biggest and poorest of Pakistan's four
Tribesmen have been waging a rebellion demanding jobs and a bigger share in the profit from Baluchistan's natural resources.
Aljazeera's correspondent in Islamabad has quoted tribal and official sources as saying that rebel tribal leader Bayt Allah Mahsud and about 150 of his followers surrendered to the Pakistani authorities in Sarugha area in South Waziristan province.
The surrender deal, which includes a pledge by Mahsud and his followers not to harbour wanted suspects and not to resist the military, came as a result of a peace agreement sponsored by chieftains of Mahsud's tribe.
Hours after the truce, however, two Pakistani journalists were killed and another was injured when tribesmen opened fire on their car in the turbulent region near the Afghan border near Wana, officials said.
A fourth journalist, Zardad Khan of Aljazeera who
was also in the car, escaped injury, hospital and media sources said.