WASHINGTON – The Obama administration acknowledged Wednesday it has killed four Americans in overseas counterterrorism operations since 2009, the first time it has publicly taken responsibility for the deaths.

Although the acknowledgement, in a letter from Attorney General Eric Holder Jr. to Congress, does not say how the four were killed, three are known to have died in CIA drone strikes in Yemen in 2011, including Anwar al-Awlaki, his 16-year-old son, and Samir Khan.

The fourth, Jude Kennan Mohammad, a Florida native indicted in North Carolina in 2009, was killed in Pakistan, where the CIA has operated a drone campaign against terrorist suspects for nearly a decade. His death was previously unreported.

Holder’s letter came the day before President Obama is due to deliver a major speech designed to fulfill a promise in his State of the Union speech in January to make elements of his controversial counterterrorism policies more transparent and accountable to Congress and the American public.

Obama is also under pressure to explain how he intends to make even modest progress on other priorities that were centerpieces of a pledge he made at the beginning of his first term. At the top of that list is closing the Guantanamo Bay prison, where 103 of the 166 detainees are on a hunger strike.

POLICIES FOR TARGETING TERRORISTS

The administration is planning to restart the transfer of the detainees, 86 of whom have been cleared to leave. A White House official said Obama “will announce a number of specific steps to advance” his goal of closing the facility.

In addition to disclosure of the four killings, Holder wrote that Obama has approved classified briefings for Congress on an overall policy document, informally called the “playbook.” The document, more than a year in the making, codifies the administration’s standards and processes for its unprecedented program of targeted killing and capture of terrorism targets outside of war zones.

Nearly 400 drone strikes, in Pakistan, Yemen and Somalia, have been launched by the CIA and U.S. military forces during Obama’s presidency. Although the administration has acknowledged the existence of the drone program and outlined its justification under international and domestic law, specific operations are considered classified.

The secrecy surrounding the program — including the criteria for choosing targets — has led to widespread opposition from international law and human rights advocates and, increasingly, from Congress and the public. Although the administration has stressed the precision accuracy of drones, independent groups have charged that thousands of civilians have been unintentionally killed.

Congressional and public criticism reached a crescendo earlier this year when Obama nominated John Brennan, then his principal counterterrorism adviser, as CIA director. Before they would confirm Brennan, lawmakers demanded access to Justice Department legal opinions justifying the killing of U.S. citizens overseas without constitutional protections.

One of them was Senate Judiciary Committee Chairman Patrick Leahy, D-Vt., who last month threatened to subpoena the administration for the opinions. Following that threat, Leahy said, the documents were produced for the committee in a classified meeting.

LAW CLASHES WITH SECURITY NEEDS

Leahy said Wednesday that Holder telephoned him to say he would receive a letter with information about the four killings and to tell him about upcoming briefings on the classified playbook. It was copied to the rest of the Judiciary Committee.

“I think it’s a significant effort at openness,” Leahy said.

Others were less certain that critics would be satisfied.

“The desire to put this on a normal, rule-of-law footing keeps clashing with the imperatives of national security, which entail extreme institutional secrecy,” said Jack Goldsmith, former director of the Office of Legal Counsel at the Justice Department. “That clash has been going on since the first day of the administration.”

Prior to the Obama administration, the only known American killed by a drone strike was Kamal Derwish, who died in a drone strike launched under then-President George W. Bush in Yemen in 2002.

In September 2011, Obama announced the death of Awlaki, a New Mexico-born cleric described as the foreign operations director for Yemen-based al-Qaida in the Arabian Peninsula, known as AQAP.

According to Holder’s letter, Awlaki was the only U.S. citizen the administration “has specifically targeted and killed.”