The Obama administration has taken the extraordinary step of authorizing the targeted killing of an American citizen, the radical Muslim cleric Anwar al-Awlaki, who is believed to have shifted from encouraging attacks on the United States to directly participating in them, intelligence and counterterrorism officials said Tuesday.
Mr. Awlaki, who was born in New Mexico and spent years in the United States as an imam, is in hiding in Yemen. He has been the focus of intense scrutiny since he was linked to Maj. Nidal Malik Hasan, the Army psychiatrist accused of killing 13 people at Fort Hood, Tex., in November, and then to Umar Farouk Abdulmutallab, the Nigerian man charged with trying to blow up a Detroit-bound airliner on Dec. 25.