The Obama administration killed four Americans in drone attacks overseas, the Justice Department acknowledged Wednesday in the first such public admission by the administration.

The day before President Obama was set to make a major public address about his counterterrorism policies, including drone use, Attorney General Eric Holder on Wednesday wrote to lawmakers saying that the administration in 2011 targeted and killed Muslim cleric and American citizen Anwar al-Awlaki. But the attack also killed Awlaki's 16-year-old son, Abdulrahman al-Awlaki, and Samir Khan. Jude Mohammed was killed in a separate strike in Pakistan.

"The decision to target Anwar al-Awlaki was lawful, it was considered, and it was just," Holder wrote to Sen. Pat Leahy, D-Vt.

The other three Americans killed in the strikes, Holder said, "were not specifically targeted by the United States."

Mohammed's was the lone death that had not been previously reported. Though it was widely assumed that the U.S. was responsible, the Obama administration had never directly acknowledged its role in the drone attacks.

Holder said Awlaki helped plan the 2009 Christmas Day bombing of a Detroit-bound plane, as well as a scheme to target cargo planes heading to the United States.

The president on Thursday will outline his administration's legal rationale for an unprecedented drone campaign overseas. While the president is winding down the wars in Iraq and Afghanistan, he is escalating to historic levels the use of remote-control killings.

Obama's counterterrorism policies have come under increased scrutiny, with some accusing the president of overstepping his constitutional authority -- and his ordered killings of Americans without due process has proven highly controversial.

The president "has made clear his commitment to providing Congress and the American people with as much information as possible about our sensitive counterterrorism operations," Holder wrote. "To this end, the president has directed me to disclose certain information that until now has been properly classified."