CAIRO — Osama bin Laden endorsed the failed attempt to blow up a U.S. airliner on Dec. 25 and threatened new attacks against the United States in an audio message released Sunday that appeared aimed at asserting that he maintains some direct command over al-Qaida-inspired offshoots.
However, U.S. officials and several researchers who track terrorist groups said there was no indication bin Laden or any of his top lieutenants had anything to do with or even knew in advance of the Christmas Day plot by a Yemen-based group that is one of several largely independent al-Qaida franchises.
A U.S. State Department spokesman said al-Qaida's core leadership offers such groups strategic guidance but depends on them to carry it out.
"He's trying to continue to appear relevant" by talking up the attempted attack by an affiliate, the spokesman, P.J. Crowley, said.
The one-minute message was explicit in its threat of new attacks. Like the airline plot, bin Laden said they would come in response to America's support for Israel.
"God willing, our raids on you will continue as long as your support for the Israelis continues," bin Laden said in the recording, which was released to the Al-Jazeera news channel.
"The message delivered to you through the plane of the heroic warrior Umar Farouk Abdulmutallab was a confirmation of the previous messages sent by the heroes of the Sept. 11," he said of the Nigerian suspect in the Dec. 25 botched attack.
"If our messages had been able to reach you through words we wouldn't have been delivering them through planes."
Directing his statements at President Obama —"from Osama to Obama," he said — bin Laden added: "America will never dream of security unless we will have it in reality in Palestine."
The message, which White House officials said could not immediately be authenticated, raised again the question of how much of a link exists between al-Qaida's top leadership along the Afghan-Pakistani border and the handful of loosely affiliated groups operating in the Arabian Peninsula, North Africa and Iraq.
The al-Qaida leader, who was last heard from in September, seemed intent on showing that he remains more than an ideological figurehead, as most analysts have suggested he has become during the terrorist network's evolution into decentralized offshoots. But some questioned whether al-Qaida's core leadership was involved.
"They weren't putting the final touches on this operation," said Evan Kohlmann, a senior investigator for the New York-based NEFA Foundation, which researches Islamic militants.
Still, the Saudi and Yemeni leaders of al-Qaida in the Arabian Peninsula, which formed in Yemen a year ago, have a long history of direct personal contact with bin Laden. It is plausible that — if they were able to — they would have informed bin Laden of the airliner plot and sought his approval, Kohlmann said.
The Yemen-based group's leader, Nasir al-Wahishi, was once bin Laden's personal secretary, and its top military commander, Qassim al-Raimi, trained in bin Laden's main camp in Afghanistan, Kohlmann said.
U.S. investigators say the suspect in the Dec. 25 attempted bombing told them he had been trained in Yemen and given the explosives there by al-Qaida in the Arabian Peninsula.
Abdulmutallab is accused of attempting to blow up the plane with an explosive powder hidden in his underwear as the aircraft approached Detroit Metro Airport. The device failed to detonate.