The lobby of the CIA Headquarters Building is pictured in Langley, Virginia, U.S. on August 14, 2008. REUTERS/Larry Downing/Files

WASHINGTON (Reuters) - U.S. intelligence and law enforcement officials told Reuters on Wednesday they have been aware of a CIA security breach, which led to the latest Wikileaks dump since late last year.

The two officials said they were focusing on contractors as the likeliest source of the leak.