The Obama administration has formally acknowledged U.S. drone strikes killed four Americans in Yemen and Pakistan. In a letter to Congress, Attorney General Eric Holder confirmed the United States deliberately killed the militant cleric Anwar al-Awlaki in Yemen in 2011. Holder also acknowledged the deaths of Awlaki’s 16-year-old son, Abdulrahman, and the elder Awlaki’s aide, Samir Khan, in Yemen, as well as the death of Jude Kenan Mohammad in Pakistan. But Holder suggested those strikes were accidental, saying all three “were not specifically targeted.” Mohammad’s killing had previously been unknown, and as of Wednesday he was still on the FBI’s Most Wanted list.