(Repeats to add update number)
* New details on how to close Guantanamo
* Obama been battered by scandals over secrecy
* Pentagon may take control of some drones from CIA
By Jeff Mason
WASHINGTON, May 23 (Reuters) - President Barack Obama will vow on Thursday to be more open to the public about the U.S. fight against terrorism and may lay out limits for the use of lethal drones abroad while sketching a vision for closing the military prison in Guantanamo Bay, Cuba.
In a major foreign policy speech after some two weeks of dealing with domestic scandals, Obama will underline his support for civil liberties in the face of recent criticism that his administration is secretive and bullies opponents.
The use by the United States of armed drone aircraft to attack extremists has increased tensions with countries such as Pakistan and drawn criticism from human rights activists at home.
Attorney General Eric Holder suggested in a letter to Congress released on Wednesday that the administration might restrict the use of drones under new "exacting standards and processes" for counter terrorism operations overseas.
Holder said the administration's principles were that "lethal force should not be used when it is feasible to capture a terrorist suspect."
The letter was seen as a precursor to Obama's address. The administration also formally acknowledged on Wednesday that it had killed four Americans in counter terrorism operations in Yemen and Pakistan, including militant cleric Anwar al-Awlaki.
After dealing with controversies about his handling of attacks in Benghazi, Libya, where four Americans were killed, Internal Revenue Service scrutiny of conservative groups, and government targeting of journalists in leak probes, Obama will try to shift the focus to his commitment to transparency and desire to shut the Guantanamo prison he promised to close years ago.
The speech is scheduled for 2 p.m. (1800 GMT) at Washington's National Defense University.
"Consistent with his commitment to being open and transparent with the American people, he will speak at length about the policy and legal rationale for how the United States takes direct action against al Qaeda and its associated forces, including with drone strikes," a White House official said.
Obama has faced pressure from both supporters and opponents to allow greater scrutiny of the secretive decision-making process guiding drone use. He said earlier this year he wanted to be more open about the issue.
"You may see some concessions from the president to explain how not only we use and justify targeted strikes but also create procedures and constraints to limit their use," said Juan Zarate, a senior adviser at the Center for Strategic and International Studies and a former counter terrorism adviser to Republican President George W. Bush.
Reuters reported earlier this week that the administration had decided to give the Pentagon control of some drone operations now run by the CIA, which conducts strikes by unmanned aerial vehicles against al Qaeda operatives in countries like Pakistan and Yemen.
CLOSING GUANTANAMO
Obama's inability to make good on a 2008 campaign pledge to close the Guantanamo Bay prison has been highlighted by a hunger strike by 103 of the 166 detainees there, 32 of whom are being force-fed to keep them from dying.
The White House, which has struggled to respond to the scandals that have dominated news coverage for days, signaled Obama would discuss the "ultimate closure" of the prison while outlining a broad counter terrorism strategy to address threats that have changed since the Sept. 11, 2001, al Qaeda-backed attacks on New York and Washington.
Officials said Obama would reiterate his commitment to closing the Guantanamo prison and lay out steps to help achieve that goal.
"The president is considering a range of options for ways that we can reduce the population there and move toward ultimate closure, some of which we can take on our own, but some of which will require working with the Congress," White House spokesman Jay Carney said on Wednesday.
One option, he said, was to reappoint a senior official at the State Department to renew U.S. focus on transferring or repatriating detainees to their home countries.
The White House declined to comment on a report in the Wall Street Journal that the administration was set to restart transfers of detainees from Guantanamo. Obama plans in the coming weeks to lift the administration's prohibition on sending detainees to Yemen, the paper reported.
Shutting Guantanamo is fraught with difficult legal and political questions.
An aide to House Armed Services Chairman Howard McKeon, a Republican, said Obama would have to give "concrete answers on what the president intends to do with those terrorists who are too dangerous to be released but cannot be tried; how he would ensure that transferred detainees can't rejoin the fight; and what he will do to detain and interrogate new terrorist captures or those very dangerous terrorists still held in Afghanistan."
(Additional reporting by Steve Holland, Susan Cornwell and Roberta Rampton; editing by Alistair Bell and Jackie Frank)
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