The government's top intelligence lawyers say Congress is adequately monitoring U.S. surveillance programs.

Those are the same assurances the White House has made consistently since details of the classified National Security Agency programs were revealed last year.

But it's become an awkward argument for the Obama administration since the head of the Senate Intelligence Committee accused the CIA of illegally monitoring Senate investigators as they carried out their oversight duties.

The congressional intelligence committees are intended to keep the government's secret activities in check. But that system is undermined if the executive branch stands in the way of Congress carrying out its oversight duties.

The lawyers spoke Wednesday at a hearing before the federal Privacy and Civil Liberties Oversight Board as part of its review of certain NSA programs.