Updated

A Web site claiming to be affiliated with Al Qaeda has called for attacks against the trans-Alaska oil pipeline.

The posting calls on jihadists to shower the pipe with bullets or hide and detonate explosives along its length, the Anchorage Daily News reported. It also calls for attacks on the Valdez tanker dock.

The unknown author encourages small cells of four or five mujahedeen, or Muslim guerrillas, living in the United States or in Canada or Mexico to mount the attacks.

The 10-page posting includes numerous links to Web sites providing maps and other information about the pipeline.

Attacking oil and gas targets in the United States and other countries is key to bringing down the economy of the "American devils," the author wrote, saying the message was posted in response to calls from Usama bin Laden and his top Al Qaeda deputy, Ayman Al-Zawahiri.

The Arabic posting was discovered and translated in late December by the SITE Institute, a Washington, D.C., nonprofit organization that tracks international terrorists.

There is no way to identify the author or know whether it could inspire an attack, said SITE director Rita Katz.

Spokesmen for the FBI and other security agencies said they were aware of the posting. None would say whether it had prompted extra measures in Alaska.

Curtis Thomas, a spokesman for the Alyeska Pipeline Service Co., the oil company consortium that runs the 800-mile pipeline, said his company also was aware of the posting.

"We're not aware at this time of any imminent threat," he said.

Company policy prohibits discussion of security procedures, staffing levels or other issues, he said.

FBI spokesman Eric Gonzales said the posting did not seem to contain information beyond what is readily available to anyone with a little digging.

"I don't think it's a secret to anyone that the trans-Alaska pipeline, the terminal at Valdez, is a critical asset not only to the state but the country," Gonzales said. "It's stating the obvious — that this pipeline plays a critical role in this nation's economy."

The Alaska pipeline carries more than 800,000 barrels of crude a day from the North Slope oil fields to the Valdez tanker port, about one-eighth of the U.S. production.

The author notes that 300,000 gallons of crude oil spewed out of a bullet hole in 2001 and that the pipeline is largely above ground, exposed and close to a highway.

A Livengood man was sentenced to 16 years in state prison after his conviction for oil pollution, criminal mischief, handling a firearm while drunk and other charges. Authorities say he shot the pipeline with a .338-caliber hunting rifle.

Pipeline operators have found numerous other bullet strikes over the years that did not puncture the pipeline's steel wall.

Security for the pipeline and Valdez tanker dock was heightened after the Sept. 11, 2001, terror attacks in New York City and Washington, D.C. One of the biggest changes was creation of a security zone the Coast Guard enforces around the dock. The zone remains in effect.

The posting includes numerous errors, including a sentence saying the pipeline starts at the North Pole and ends at Valdez "on the Atlantic Ocean."

Katz, the SITE director, said her organization has analyzed and translated many terrorism-related Web postings for its clients, including oil companies, and this one stood out.

"When I saw this message, I was shocked," Katz said. It was much longer, more thoughtful and more fully researched than the normal posting, she said.

The posting might have come from anyone. What's more important than the source is the influence it might have.

"Once there's an idea there, then you don't know who saw that idea and might take the initiative and go forward," she said.

"We take all of these matters quite seriously," said John Madden, state Homeland Security director. However, the posting was "not any great, analytical document," but rather a collection of information available from open sources.

Last month, federal pipeline regulators ordered Alyeska to develop new spill cleanup drills with "terrorist attack scenarios" in mind.