Reeling under pressure from the Capitol Hill and from human rights groups over its ever-expanding use of drone strikes on foreign soil, the Obama White House has relented and agreed to share with select members of the U.S. Congress a secret memo outlining the justification for its targeted killings.

President Barack Obama’s decision to release the memo comes in the wake of NBC news channel obtaining and publishing on the Internet a White Paper on the administration’s support for drone attacks.

An anonymous administration official speaking to media here said that Mr. Obama had personally directed the Justice Department's Office of Legal Counsel to grant Congressional Intelligence Committees access to a classified memo outlining the administration's legal justification for targeted killing, an administration official said Wednesday evening.

News of the White House’ decision also came hours before Thursday’s Senate confirmation hearing for John Brennan as the Director of the Central Intelligence Agency. In this light the hearing is likely to see increased attention on Mr. Brennan’s support for the CIA’s reliance on drones, reports suggested.

Mr. Brennan was compelled to pull out of from nomination to the same post four years ago, after doubts were raised over his support for “extraordinary rendition” and “enhanced interrogation” techniques, or torture, during his time in the George W. Bush administration’s War on Terror. This week the Obama administration said it would permit members of the House of Representatives and Senate Intelligence Committees to see the memo.

Earlier this week lawmakers had written to Mr. Obama pressing the Department of Justice for the release of documents backing the targeted assassination of American citizens suspected of involvement in terror attacks. Most notably this included American-born cleric Anwar al-Awlaki, who was killed in September 2011 after a U.S. missile struck the vehicle carrying him.

The White Paper leaked to NBC revealed that the White House believed that high-level administration officials, and not just the Mr. Obama, could order the killing of “senior operational leaders” of al Qaida or an associated force even without evidence they are actively plotting against the U.S. “A lawful killing in self-defence is not an assassination,” according to that paper, as quoted in the NBC report.

The Obama administration’s covert operations are facing a turbulent week in Washington. In addition to Mr. Brennan and the drone programme being closely scrutinised by Congress, the Washington Post came under fire for seeking to protect the White House from criticism by withholding for entire year confidential information it had obtained on the existence of a secret drone base in Saudi Arabia.