WASHINGTON — Remnants of a surface-to-air missile discovered at a Saudi military base used by U.S. troops likely belonged to Al Qaeda operatives, prompting an FBI warning about possible missile attacks against U.S. aircraft, according to a classified alert issued this week.
Intelligence officials have suspected for years that Osama bin Laden's Al Qaeda terrorist network may have access to surface-to-air missiles, but the discovery of a missile-launching tube from a shoulder-mounted missile at the Prince Sultan Air Base appeared to offer troubling confirmation.
In an alert obtained by The Times, FBI officials said an investigation has revealed that the missile remnants discovered in early May are "likely" connected to an effort by Al Qaeda to target U.S.-led coalition forces on the Arabian Peninsula.
While the FBI alert cautioned that it has no specific information indicating that Al Qaeda is planning to use surface-to-air missiles in terrorist attacks, it warned law enforcement agencies within the United States to be "alert to the potential use [of the missiles] against U.S. aircraft."
The FBI warning does not say how investigators concluded that Al Qaeda was likely behind the placement of the missile at the military base, but it notes that Al Qaeda has targeted both the U.S. airline industry and U.S. military in Saudi Arabia.
The 3-foot-long launching tube was found two weeks ago inside the perimeter of the base, two miles from a runway used by U.S. warplanes at the sprawling facility. It appears to have come from an older model, relatively crude SA-7 missile first made by the Russians in 1969. The missile had been fired, though it is not known when.
The type of missile is known as a MANPAD, or Man Portable Air Defense System, and it has a range of up to 3.5 miles, according to the FBI alert.
An FBI official who asked not to be identified said that "we've had the concern for years that shoulder-fired antiaircraft missiles would be the perfect terrorism weapon. You could hide in the bushes somewhere around a major U.S. aircraft and when a plane was coming in for a landing or taking off, you could let one of those fly and take down a plane. It's a terrifying prospect."
Surface-to-air missiles are only the latest in a long line of weapons that authorities have warned both publicly and privately could be used by terrorists to inflict mass destruction. Other threats cited since Sept. 11 include trains, subways, cargo containers, commercial trucks, crop dusters, "walk-in" suicide bombers, scuba divers and many others.
The older-style Russian missiles "are available on the gray market, and they're relatively small, so it is within the realm of possibility that they could use that type of method to launch an attack," said another U.S. government official who also requested anonymity. "That's something we're mindful of and concerned about."
The discovery at the remote Saudi site so close to U.S. personnel and warplanes, however, has raised the concerns about such an attack to a higher level within the United States, and it is also likely to deepen Pentagon concerns about the military's presence in Saudi Arabia.
Pentagon officials revealed two weeks ago that they had found the missile parts on the Saudi base, but they downplayed the significance of the discovery and, unlike the FBI's warning issued Wednesday, did not mention any links to Al Qaeda at that time. Military officials said Friday that they remain uncertain about the significance.
Marine Corps Capt. Robert Riggle, a spokesman for Central Command in Tampa, Fla., said Friday that "it was just found laying there; no one knows how it was fired and how it got there." In the view of military authorities "there's really not that much to it," he said.
He said U.S. forces were unaware of any sign that any MANPAD had been fired at U.S. fliers.
Some questions may remain unanswered, however, because the Saudis destroyed the missile tubing after it was photographed.
U.S. forces were moved to the Prince Sultan Air Base in the center of Saudi Arabia in the 1990s to make the American troops a less visible presence in the kingdom, where many are hostile to them. But as the years have passed, concern has grown over threats to personnel and hardware. Meanwhile, their Saudi government hosts worry that the U.S. presence has stirred domestic opposition.
Daniel Goure, a former defense official now at the Lexington Institute think tank in suburban Washington, D.C., said the discovery points to the risk that U.S. forces face in so many places.
"A lot of people there don't like the United States, and the borders are porous," he said.
He noted that driving the United States out of Saudi Arabia was Bin Laden's top goal and that the dissident has been linked to a 1995 bomb blast in Riyadh that killed five American troops. And terrorists struck the Khobar Towers Air Force Base in Dhahran, Saudi Arabia, in 1996, killing 19.