LOS ANGELES, Nov 27: The US oil and gas industry has been put on high alert after a Federal Bureau of Investigation warning that Osama bin Laden might have ordered retaliatory strikes against the North American natural gas facilities in event of his arrest or death, industry sources said on Monday.

Reports said that the warning issued by the FBI last week was general and singled out no specific target, but referred specifically to the natural gas infrastructure such as pipelines.

There are thousands of miles of gas pipeline, most of them buried, crossing the United States and Canada. Thirty interstate gas pipelines carry around 90 per cent of the natural gas, according to the Interstate Natural Gas Association of America.

One source characterized the warning as similar to one issued earlier this month fearing attacks against the West Coast bridges that prompted security alerts.

The FBI alert prompted the American Petroleum Institute, which is the lead industry group coordinating with the FBI and the Energy Department on security matters, to issue a warning to oil and gas companies.

“We have received uncorroborated information that Osama bin Laden may have approved plans to attack natural gas supplies in the United States,” said a FBI memo, adding that the information was “from a source of undetermined reliability.”