There have been explosions in two of the main pipelines in Pakistan's Punjab province, badly disrupting the supply of natural gas to large parts of the country.
The exact cause of the explosions, in the district of Sadiqabad, is still not known.
Officials say the manner in which explosions occurred in quick succession in two of Pakistan's most important gas pipelines suggests sabotage.
Earlier this year gas pipelines were blown-up by rockets during a major clash between the Bugti and Mazari tribes in Balochistan province.
The powerful explosions in the early hours of Tuesday sent shockwaves in and around the district of Sadiqabad.
The main pipeline, supplying gas from Balochistan's Sui gasfields, was the first to explode with a huge bang.
Observers say the government's apparent inability to take action against the tribal leaders...has created uncertainty about the regular supply of the natural gas
It immediately caught fire, burning down three small houses, and injuring a couple of people.
Eyewitnesses say within a couple of hours there was another explosion, this time in a pipeline that supplies natural gas from the Qadirpur fields of Sindh province.
A senior official of the state-owned gas company, Abdur Rasheed Lone, told reporters in Lahore that it was possible that one of the two tribes involved in the earlier incidents in January may also have blown-up the pipelines in the Punjab's Sadiqabad district.
But he said the real cause would be known only when investigations were completed.
Mr Lone said although repair work on the damaged pipelines has started, the supply of gas to most of the industries in the Punjab and Northwest Frontier province would remain suspended at least until Wednesday.
However, he said efforts were being made to restore gas supplies to most domestic users as soon as possible.
After January incidents, the authorities increased security along the crucial gas pipelines in Balochistan.
But observers say the government's apparent inability to take action against the powerful tribal leaders involved in the bloody feud has created uncertainty about the regular supply of the natural gas to large parts of the country.