Natural-gas suppliers in Maine and elsewhere in the Northeast have increased security following an FBI warning that pipelines and facilities could be targeted by terrorists.

The FBI warned energy companies earlier this month that Osama bin Laden may have approved such attacks if either he or Taliban leader Mullah Omar are either captured or killed.

Industry officials said additional security measures are in place to safeguard the gas supply to 2.2 million customers in New England.

“We as an industry are on an extremely heightened state of alert,” said Tom Kiley, president of the New England Gas Association.

Maine has about 25,000 natural gas customers. Most are in the Portland and Lewiston areas, but there are also some industrial customers around Bangor and Brunswick.

Two natural gas pipelines cross Maine. The Maritimes & Northeast pipeline runs from Portland to Augusta to Calais, and then out to Sable Island off Nova Scotia. The Portland Natural Gas Transmission System pipeline runs from southern New Hampshire through York County to Portland, then on to Pittsburg, N.H., into Canada.

Kiley would not give details on the precautions taken around the gas lines and distribution facilities in response to the threat.

“We can’t and won’t discuss specific security measures, but as an industry we are certainly reacting to this and taking it seriously,” Kiley said from his office in Needham, Mass. “We have more people guarding natural gas facilities since Sept. 11, and as result of this latest threat, more still.”

The state will help with security if asked, but so far no utility companies have requested assistance, according to Rayna Leibowitz, chief of the planning division for Maine Emergency Management Agency.

A spokeswoman for Maritimes & Northeast would not say what additional security measures – if any – had been adopted. But Marylee Hanley said the company has been on heightened alert since Sept. 11 and continues to respond to alerts from federal agencies.

“I can’t tell you any special steps we’ve taken. We’re trying to protect the communities in which we operate,” she said from her office in Boston.She added that the company’s control center in Houston can isolate a break in the pipelines using remote-controlled valves.

Mark Robinson lives about 500 feet from an underground gas line in a rural part of Kennebunk. He said it isn’t worth worrying about the possibility of someone blowing up the pipeline.

“It would be an awful thing if someone did that, but I’m not that worried about it,” he said. “The pipeline is probably 1,500 miles long, and even if they were to do something, I can’t imagine it would be out here.”