An unnamed spokesman for the Sui Northern Gas Co. said part of a natural gas pipeline was destroyed in a militant attack. That left consumers in parts of Karachi with a natural gas shortage, the Daily Times, a Pakistani newspaper, reports.
There were no claims of responsibility for the attack.
The SNGC spokesman said the bombing created a 190-million-cubic-foot shortfall in the natural gas pipeline system. Repair work was under way, though no estimate on when service would resume was announced.
Pakistan is struggling to cope with a lingering energy crisis because of a shortage of natural gas. Pakistani President Asif Ali Zardari and Iranian President Mahmoud Ahmadinejad met last month at the countries' border to mark the start of construction in Pakistan for a $7.5 billion natural gas pipeline from Iran.
The project has faced a series of delays since it was proposed in the 1990s. The United States has opposed the plan because of the potential financial benefit to Iran and its nuclear program.