The Obama administration has authorised the CIA to hunt down an American-born Muslim cleric who is believed to be hiding in Yemen.
Anwar al-Awlaki is accused of being linked to attacks on the US, including the attempted bombing of a US-bound airliner on Christmas Day and a rampage at an American army base in which 13 people were shot dead.
Mr al-Awlaki used to be an imam based in the United States, before relocating to Yemen.
The BBC reports it is highly unusual for the Obama administration to approve a drone strike on a US citizen.
