Pakistan has deployed troops at its largest natural gas field after days of clashes with tribal militants left at least eight people dead.
There have been rocket attacks and clashes for days
The main plant at the Sui complex in Balochistan province is shut. Sui provides about 60% of Pakistan's gas.
Tribesmen have been firing rockets at gas facilities, and stormed the complex on Tuesday before being driven back by security forces, officials say.
Clashes began on Friday after claims a female doctor had been gang-raped.
The woman is said to be in her thirties and employed by state-owned Pakistan Petroleum Limited. It is not clear who might have carried out the alleged rape, but tribesmen blame security forces.
In an unrelated incident on Wednesday, a group of between eight and 11 workers for the Pakistan Water and Power Development Authority were abducted by bandits in the Sindh/Balochistan border area.
There have been a series of bomb explosions in the provincial capital, Quetta, and other parts of Balochistan, one of the country's poorest areas, over the past year.
Disgruntled tribesmen seeking a larger share of oil and gas wealth are blamed for the attacks.
On Tuesday, President Pervez Musharraf warned tribesmen to stop their violence - and threatened to use force if they did not.
"We are watching it with great concern," he told private Geo television.
He had this message for the militants: "Don't push us... it is not the 1970s, and this time you won't even know what has hit you."
He was referring to a crackdown by the military in the 1970s on separatist rebels in the area.
Paramilitary soldiers were sent to the Sui complex, 290km (180 miles) south-west of Quetta, on Tuesday after tribesmen overpowered guards there.
Officials say the tribesmen damaged pipelines and a purification plant before paramilitary frontier forces drove them out.
"Three paramilitary soldiers were killed and five others were wounded in fighting on Tuesday evening as security forces ejected the troublemakers from the gas field," military spokesman Maj Gen Shaukat Sultan told Reuters news agency.
He said two civilians, including a child, had died in the crossfire. The number of casualties sustained by tribesmen is unclear.
Provincial officials say that in all at least eight people have been killed in clashes since Friday. Unconfirmed reports put the figure higher.
Series of attacks
Supplies of gas to power stations and fertiliser factories in neighbouring provinces have been stopped for a second day following the clash.
A December bomb attack in Quetta killed at least 11 people
"The plant has been closed as a precautionary measure because if, God forbid, the plant was hit it would result in horrible tragedy," one senior gas official, Rashid Lone, told the AFP news agency.
There are about 6,500 paramilitary personnel stationed at Sui, backed by some 1,500 regular troops and 750 personnel from the Defence Security Guards.
Tribesmen say they fear a massive operation against them.
"They [army and paramilitary forces] have thrown a ring around us," tribal chief Nawab Akbar Bugti told the BBC News website.
Locals in Balochistan say they face a situation of near war in the province. Rocket attacks against gas facilities are a regular occurrence.
There have been more than 30 bomb attacks in Quetta alone in the last year. The most deadly, last December, killed at least 11 people and wounded more than 30 others.
A group calling itself the Balochistan Liberation Army said it carried out the bombing in its fight against what it sees as the dominating influence of Punjabis on local political life.