Operatives have been working in the country for several weeks, collecting intelligence for military operations and trying to figure out the loyalties of opposition fighters, officials say.
President Obama signed a secret finding several weeks ago authorizing the CIA to arm and otherwise support the Libyan rebels, the officials say. But no weapons have been shipped yet.
In a related development, Libya's foreign minister, Moussa Koussa, defected to Britain on Wednesday, according to the British foreign ministry.