National Security Agency chief Gen. Keith Alexander will answer senators’ questions about the agency’s domestic surveillance program behind closed doors on Thursday.

He was expected to face senators on Wednesday but, because his answers require the disclosure of sensitive details about NSA operations, the meeting will no longer be public.

The hearing — led by Democratic Sen. Barbara Mikuslki, chairwoman of the Senate Appropriations Homeland Security Committee — was meant to update the appropriations committee on cybersecurity efforts.

Both the Obama administration and the NSA have been in damage control mode since leaks about the agency’s surveillance program were first published last week.

When pressed by members for details about its collection efforts, Alexander said that the NSA would be making more information known to the public within a week’s time.

“I want people the American people to know we’re being transparent,” he said.

Vermont Democratic Sen. Patrick Leahy, after asking Alexander defend the NSA’s broad collection of phone metadata in the wake of the Boston Marathon Bombing, said that maybe the FBI should have shared what it knew with the Boston authorities instead.

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