WASHINGTON (AP) - President Barack Obama is set to at least partially lift the veil of secrecy surrounding US-directed drone strikes around the world, a key component of counterterrorism strategy, as he outlines the contours of the continuing threat to American security.
On the eve of the president's speech at the National Defence University, the Obama administration disclosed for the first time that a fourth American citizen had been killed in secretive drone strikes abroad. The killings of three other Americans in counterterror operations since 2009 were widely known before a letter from Attorney General Eric Holder to Senate Judiciary Committee Chairman Patrick Leahy acknowledged the four deaths.
President Obama's speech is expected to reaffirm his national security priorities - from homegrown terrorists to killer drones to the enemy combatants held at the military-run detention centre at Guantanamo Bay, Cuba - but make no new sweeping policy announcements.
The White House has offered few clues on how the president will address questions that have dogged his administration for years and, critics say, given foreign allies mixed signals about US intentions in some of the world's most volatile areas.
Mr Obama will try to refocus an increasingly apathetic public on security issues as his administration grapples with a series of unrelated controversies stemming from the attack on a US compound in Benghazi, Libya, the tax collection agency's targeting of conservative groups and government monitoring of reporters. His message will also be carefully analysed by an international audience that has had to adapt to what counterterror expert Peter Singer described as the administration's disjointed and often short-sighted security policies.
"He is really wresting with a broader task, which is laying out an overdue case for regularising our counterterrorism strategy itself," said Dr Singer, director of the Brookings Institution's 21st Century Security and Intelligence Centre in Washington.
"It's both a task in terms of being a communicator, and a task in term of being a decider."
The White House said Mr Obama's speech coincides with the signing of new "presidential policy guidance" on when the US can use drone strikes, though it was unclear what that guidance entailed and whether Mr Obama would outline its specifics in his remarks.
Chief among the topics the speech will focus on, officials said, is the administration's expanded use of unmanned spy drones to kill hundreds of people in Pakistan, Yemen and other places where terrorists have taken refuge.
Mr Obama has pledged to be more open with the public about the scope of the drone strikes. But a growing number of lawmakers in Congress are seeking to limit US authorities that support the deadly drone strikes, which have targeted a wider range of threats than initially anticipated.
The president is expected to talk generally about the need for greater transparency in the drone strikes and may allude to the desire to give greater responsibility for those operations to the military. But he is likely to tread carefully on an issue that involves classified CIA operations.
The US military has begun to take over the bulk of the strikes, replacing the Central Intelligence Agency in nearly all areas except Pakistan, according to an administration official who was not authorised to discuss the plans on the record and spoke on condition of anonymity. That shift in responsibility has given Congress greater oversight of the secretive program.
Mr Obama "believes that we need to be as transparent about a matter like this as we can, understanding that there are national security implications to this issue and to the broader issues involved in counterterrorism policy," White House spokesman Jay Carney told reporters on Wednesday.
"He thinks (this) is an absolutely valid and legitimate and important area of discussion and debate and conversation, and that it is his belief that there need to be structures in place that remain in place for successive administrations," spokesman Carney said.
"So that in the carrying out of counterterrorism policy, procedures are followed that allow it to be conducted in a way that ensures that we're keeping with our traditions and our laws."
In a letter on Wednesday to congressional leaders, Attorney General Holder said only one of the US citizens killed in counterterror operations beyond war zones - Anwar al-Awlaki, who had ties to at least three attacks planned or carried out on US soil - was specifically targeted by American forces. He said the other three Americans were not targeted in the US strikes.
The deaths of three of the four, including al-Awlaki's 16-year-old son, Abdulrahman, were already known. Mr Holder's letter revealed the killing of Jude Kenan Mohammad, who was indicted by federal authorities in 2009 as part of an alleged homegrown terror plot to attack the US Marine Corps base at Quantico, Virginia. Before he could be arrested, authorities said, Mohammad fled the country to join jihadi fighters in the tribal areas of Pakistan.
For months, Congress has urged Mr Obama to release a classified Justice Department legal opinion justifying when US counterterror missions, including drone strikes, can be used to kill American citizens abroad. Several lawmakers declined immediate comment Wednesday on Mr Holder's letter or Mr Obama's speech.
Human rights watchdogs, however, were not immediately appeased.
Human Rights First legal director Dixon Osburn welcomed the White House's pledge for more transparency but remained "deeply concerned that the administration appears to be institutionalising a problematic targeted killing policy without public debate on whether the rules are lawful or appropriate".
"The American public deserves to know whether the administration is complying with the law, and Congress should debate the legal and policy implications of our targeted killing operations," he said in a statement.
In re-affirming his pledge to close the detention centre at Guantanamo, Mr Obama will push in the speech for a renewed effort to transfer its 166 detainees to other countries. Congress and the White House have sparred since Mr Obama took office in 2009 over the fate of the suspects and whether they can be brought to trial on US soil. In the meantime, the detainees have been held for years with diminishing hope that they will charged with a crime or be given a trial.