Two shoulder-fired missile launchers found outside the airport in Mombasa, Kenya, last week are from the same production batch as a launcher used to fire at a U.S. fighter jet in Saudi Arabia last May, Pentagon officials told Fox News on Monday.
The finding has led the Pentagon to conclude that the twin attacks against an Israeli charter airliner and an Israeli-owned hotel in Kenya last Thursday were almost certainly the work of Al Qaeda operatives.
U.S. officials told Fox News that Al Qaeda purchased a "batch" of SA-7 shoulder-fired launchers, and that the devices found in Mombasa and Prince Sultan Air Base came from the same collection.
Investigators compared the lot numbers on the two launchers in Kenya with the number on a discarded launch tube recovered outside Prince Sultan Air Base in Saudi Arabia, and discovered they were very close, suggesting the missiles were purchased as a group, officials said.
It is unclear where or when the missiles were purchased.
Thousands of this kind of portable heat-seeking missile, known in the West as the SA-7b Grail, have been produced in Russia, Eastern Europe, China, Yugoslavia, Egypt and elsewhere. They chase the heat produced by an airplane engine and explode, but are effective only when the plane is flying low and slow.
A 30-year-old design also known by its Russian name, Strela, they are available on illicit arms markets. U.S. officials said they can cost between $500 and $5,000; newer, better shoulder-fired surface-to-air missiles can go for $10,000 or $20,000.
On Thursday, attackers launched two missiles at an Arkia Airlines Boeing 757 just after it took off from Mombasa, Kenya, for Tel Aviv, Israel, with 261 passengers and 10 crew members. They missed and the plane, an Israeli charter, landed safely at its destination.
Moments before, a vehicle bomb exploded outside an Israeli-owned hotel in Mombasa, killing 10 Kenyans, three Israelis, and the three homicide bombers. Officials have said they suspected Al Qaeda, or an affiliated Islamic extremist network in Somalia.
The plane attack was similar to a high-ranking Sudanese Al Qaeda operative's attempt to shoot down a U.S. military aircraft in May.
That operative, Abu Huzifa, fired an SA-7 at a military plane flying near Prince Sultan Air Base, where many U.S. forces are based. The attack failed and went undetected until Saudi security forces found the abandoned launcher.
Abu Huzifa was detained in Sudan by local authorities a short time later. He admitted launching the attack, U.S. officials have said.
The May attack led to an FBI warning suggesting terrorists may try to target civilian aviation with missiles.
President Bush called Kenyan President Daniel arap Moi on Monday to offer condolences for the attacks there.
In an early-morning telephone conversation, Bush also offered United States assistance in the investigation, White House spokesman Ari Fleischer said. The United States has been helping behind the scenes for days.
The two leaders "shared their commitment to bring to justice those responsible for the attack," Fleischer said. "The president expressed his appreciation for the cooperation of President Moi and the Kenyan government in the global fight against terrorism."
Moi is to visit Bush at the White House on Thursday, and Bush will visit Africa next month.
Asked about the attack, Fleischer said: "We are looking into it. There is nothing conclusive to report. There are suspicions that Al Qaeda is involved."
Fox News' Bret Baier and The Associated Press contributed to this report.