The man described as al-Qaeda's chief in the Gulf and a suspected planner of the bombing of the US warship USS Coleis in US custody, officials said.
Mr Abd al-Rahim al-Nashiri, who was born in Mecca, Saudi Arabia, was among the top dozen al-Qaeda leaders sought by US authorities. He has spent time in Yemen, Afghanistan and Pakistan, officials said, declining to reveal where he was captured.
"He's a top al-Qaeda operational planner for the Arabian Peninsula, he was captured in recent weeks and is currently in US custody at an undisclosed location," an official said.
Mr Al-Nashiri's alleged ties to al-Qaeda leader Osama bin Laden date from the 1980s in Afghanistan, when they were fighting the Soviet invasion.