The raid targeted Saleh Ali Saleh Nabhan, a Kenyan-born Al Qaeda operative wanted for his alleged involvement in the 1998 bombings of US embassies in Kenya and Tanzania, a 2002 bombing of an Israeli-owned hotel in Kenya, and the near-simultaneous, failed missile strike on an Israeli airliner taking off from Mombasa's airport.
Ali Nabhan and three associates died in Monday's raid, media reports said. The operation reflects both growing concerns that Somalia is becoming a haven for terrorists, and the US' willingness to hunt down and kill Al Qaeda members anywhere in the world.
Several sources tell ABC News at least one U.S. helicopter fired on a convoy carrying suspected al Qaeda targets in southern Somalia. An American official says a U.S. Navy ship was also nearby to monitor the situation and provide assistance if needed.
Ali Nabhan's death has not yet been officially confirmed, but sources tell ABC News that his body is now in U.S. custody.
Fox News gave more details, citing "two senior U.S. military officials," saying that US President Barack Obama signed an "Execute Order" for Ali Nabhan early this month, and that the special forces involved were US Navy Seals.
They called it operation Celestial Balance: at least two AH-6 Little Bird helicopters deployed from one of two U.S. Navy vessels near Somalia's coast strafed a vehicle Nabhan was using to go back and forth between meetings.
Intelligence operatives had been monitoring Sabhan prior to the attack. The helicopters passed once, firing on the vehicle, and then circled back around to retrieve the body so they could make a positive identification, according to an official.
Obama's conciliatory message to the Muslim world and plans to close Guantánamo Bay have been accompanied by a determination to fight al-Qaeda, with the organization suffering significant losses in CIA Predator drone attacks in Pakistan's tribal areas. By striking without warning in Somalia, Washington reinforces the message that no one is beyond its reach.
According to this profile on Globaljihad.net, Ali Nabhan was born in Mombasa, Kenya, in 1979 to a relatively well-to-do family, and it was "not clear" what had radicalized him. He was believed to be the head of an Al Qaeda cell in Mombasa, and to handle communication between that cell and Osama bin Laden.