A gas pipeline in Pakistan's south-western Balochistan province has been blown up, officials say.
A spokesman for the Sui Southern Gas company said the pipeline was located some 350km (218 miles) south of the regional capital, Quetta.
Pipelines are targeted regularly in this gas-rich province where tribal groups are pushing for greater autonomy.
The attack will affect supplies to Karachi and areas of Balochistan.
The director of the gas company, Naeem Akhwand, told the BBC that major infrastructure consumers, like the Water and Power Development Authority, Karachi Electricity Supply Company and Pakistan Steel Mills would be affected by the attack.
Officials say two gas pipelines were also blown up in the area three days ago, disrupting work in factories of Punjab and North West Frontier Province.
Pakistan's government says that Baloch rebels have set up training camps in the mountains and blames them for the attacks.
Officials say attacks have been stepped up after the government started military activities in the Dera Bugti and Kohlu areas of Balochistan.
President Pervez Musharraf has, in the past, accused tribal leaders of putting up armed resistance to his plans to build a sea port and road network to turn Balochistan into a major trading zone.
But Baloch tribal leaders say their struggle is for greater provincial autonomy and an increased share of mineral resources from the gas and oil rich province.