The U.S. Justice Department has formally acknowledged that the United States has killed four American citizens in drone strikes in Yemen and Pakistan since 2009.
The official disclosure came Wednesday in a letter from U.S. Attorney General Eric Holder to congressional leaders, on the eve of a major national security speech by President Barack Obama.
In the letter, addressed to Senate Judiciary Committee chairman Patrick Leahy, Holder said the deaths occurred in U.S. counterterrorism operations against al-Qaida militants and their affiliates.
The five-page document confirms that U.S. forces in 2011 deliberately killed Anwar al-Awlaki, the radical cleric born in the United States in 1971 while his Yemeni father was doing graduate studies at U.S. universities.
It says three other Americans were killed in that time frame, though not directly targeted by U.S. forces. Those deaths included those of Samir Khan, who was killed in the same strike that killed the cleric, and al-Awlaki's son, who was killed days later. The fourth victim, identified as Jude Kenan Mohammed, was killed in a strike in Pakistan.
The letter describes the senior Awlaki as the person who planned the attempted bombing of a Detroit-bound airliner in 2009, and says he played a key role in a 2010 failed plot to bomb cargo planes bound for the United States.
Holder last year laid out the Obama administration's legal thinking on the drone strikes. He told students at Northwestern University's law school that American citizens found to be operational terrorists posed an "imminent threat" of violent attack. An unclassified document prepared for congressional review last year expanded on the legal analysis. It was leaked to the press earlier this year.