An undersea cable carrying data between Pakistan and the outside world has developed a serious fault, virtually crippling data feeds, including the Internet, telecommunications officials said.

The system crashed late on Monday and was still down on Tuesday evening. Many offices across the country ground to a halt as people realized it was not one of Pakistan’s regular, but usually brief, technical hitches.

“It’s a worst-case scenario. We are literally blank,” said a senior foreign banker who declined to be identified.

An official at the Karachi stock exchange said Pakistan’s main bourse was unaffected as it had its own internal trading system.

Officials at Pakistan Telecommunication Ltd, which operates the link, said the fault was in an undersea cable and had been caused by a power supply problem.

Fixing it would entail an interruption for other countries using the link, including India, Dubai and Oman, one company official said.

“To reconfigure the power supply system and set the fault right there needs to be an interruption of up to two hours,” said PTCL official Mashkoor Hussain.

But the impact on neighboring countries would be limited and the repairs would begin at 4 a.m. on Wednesday (2300 GMT on Tuesday) to minimize any disruption, he said.

“They have more than one cable. Their systems will continue working.”

Telecommunications officials in those countries had been consulted and had given the go-ahead for the repairs, he said. “Hopefully it will be repaired by tomorrow morning.”

Airlines and credit card companies were among the businesses hit by the crash.

“It’s a total disaster,” said Nasir Ali, commercial director of the private Air Blue airline. “We have a Web-based booking system which has totally collapsed.”

PTCL provided satellite back-up for the link, which meant some people were able to get access to a very slow Internet connection, Hussain said, but users complained it was too slow to be of any use.

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