A Saudi tip about a possible al Qaeda effort to bring down airplanes was relayed to US authorities in early October, nearly three weeks before the group's Yemen affiliate tried to ship mail bombs to the US in cargo planes, US intelligence officials said on Friday.
The Saudi intelligence tip helped to head off what could have been a devastating series of plane explosions. Western officials credit the Saudis with playing a crucial role in finding two mail bombs recovered last week in Dubai and Britain before they reached the US.
On Friday, the Yemen-based al Qaeda in the Arabian Peninsula claimed responsibility for sending the two bombs and threatened more attacks on civilian and cargo planes. The group also said it had a role in the crash of a UPS cargo plane in Dubai in September, but investigators so far have insisted an accident was at fault.
The Saudi tip in October contained no mention of cargo planes, or any details of the plot carried out last week, said US officials, speaking on condition of anonymity to discuss classified matters. But they said it gave the US and other Western officials enough of a warning to know what to look for when another Saudi tip arrived last week.
A CIA spokesman on Friday night cited several allies that have provided key intelligence about terrorist activities.
"Over the past several months, we received intelligence - which was shared across our government - from our foreign partners about threats from AQAP and other terrorist groups," said CIA spokesman George Little.
"The United States receives this kind of information from other governments on a regular basis, as you would expect. Last week, we received specific intelligence that allowed the United States and our allies to disrupt the cargo plot. Our actions were swift and aggressive."
Another US official said the Yemeni terror group's interest in plane attacks has been apparent since its failed Christmas Day attempt last year to bring down a Detroit-bound plane with explosives hidden in the underwear of a suicide bomber.
Both the Christmas Day attack and the mail bombs sent last week used a powerful industrial explosive PETN, and the AQAP's top bomb maker is considered a top suspect in both attempts.
But although the tip relayed in October did raise alarms about a plane attack, it did not mention cargo planes or where the plot might originate or even who the attackers might be, the official said.
US intelligence had been monitoring steady intelligence on a possible attack such as this since early September, one US official has said. And in late September, authorities also intercepted a group of packages shipped to Chicago which in retrospect is now seen as a likely test run by the terror group to gauge the logistics of shipping bombs by air to the US.
The report on the Saudi tip in October was first reported on Friday by The New York Times and the German news magazine Der Spiegel. On Friday, AQAP said it would continue to strike American and Western interests and specifically said it would target civilian and cargo aircraft.
"We have struck three blows at your airplanes in a single year," the group said in a message posted on a militant website. "And God willing, we will continue to strike our blows against American interests and the interests of America's allies."
The authenticity of Friday's claim could not be immediately verified. A US intelligence official said authorities are not surprised to see this claim now.
Authorities in the US and the UAE have said the September 3 crash of the UPS plane in Dubai shortly after takeoff was caused by an onboard fire, but investigators are taking another look at the incident following the parcel bomb plot.
A security official in the UAE familiar with the investigations into the UPS cargo plane crash in Dubai and the mail bombs plot told The Associated Press on Friday that there is no change in earlier findings and that the UPS crash in September was likely caused by an onboard fire and not by an explosive device.
"There was no explosion," the official said, speaking on condition of anonymity under standing UAE rules on disclosing security-related information.
A UPS spokesman, Norman Black, said his company had "no independent knowledge of this claim by al Qaeda," and noted that both UAE officials and US National Transportation Safety Board officials have so far ruled out the possibility of a bomb as cause in the crash.
In its statement, al Qaeda's Yemeni offshoot said that it "downed the UPS airplane but because the enemy's media did not attribute the act to us, we kept silent about the operation until we could return the ball once more.
"We have done that, this time with two explosives, one of them sent via UPS, the other via FedEx."
It said that its "advanced explosives" give it "the opportunity to detonate (planes) in the air or after they have reached their final target, and they are designed to bypass all detection devices."
Both mail bombs were hidden inside computer printers and wired to detonators that used cell-phone technology and packed powdered PETN, a potent industrial explosive.
The message also directed a warning to Saudi Arabia, warning: "God's curse on the oppressors."