U.S. officials say the Obama administration has authorized the CIA to capture or kill a U.S.-born radical Muslim cleric alleged to be an al-Qaida operative.
Anwar al-Awlaki is believed to be hiding in a mountainous region of Yemen.
Officials quoted in U.S. news reports say Awlaki has been added to a target list after a review of his activities, with officials believing he shifted from encouraging attacks to taking on a role with al-Qaida in the Arabian Peninsula.
Last month, in an audio message, Awlaki called on American Muslims to revolt against the U.S. government because of its actions against other Muslims around the world.
Awlaki, who was born in the U.S. to Yemeni parents, has admitted to communicating with Major Nidal Hasan, who is accused of killing 13 people at a U.S. military base in the southwestern U.S. state of Texas last year. He also says the Nigerian man accused of trying to bomb a U.S.-bound passenger jet last year was his student.
Yemen has intensified its campaign against al-Qaida militants after the group's local branch claimed responsibility for the failed bombing of the plane in December.
Some information for this report was provided by AP.