Since the agencies joined anti-terror efforts under the Justice Department five years ago, they have battled each other for power, squandering time and prompting extra work for both sides, The Washington Post (NYSE:WPO) reported Saturday.

"A lot of these things require a little adult supervision from the Justice Department or Congress, which will resolve a lot of the food fights these two agencies find themselves in," said Michael A. Mason, former head of the FBI Washington field office.

The merging of the agencies was intended to reduce existing hostility between them after the Sept. 11, 2001, terrorist attacks. Members of both agencies said tensions arise from time to time.