No evidence of al Shabaab threat against U.S., attorney general says

WASHINGTON (Reuters) - The United States has no specific, credible evidence of a threat against it from al Shabaab, the Somali militant group that raised security concerns with its attack on a Nairobi mall, U.S. Attorney General Eric Holder said on Thursday.

Holder said at a news conference at the Justice Department that he was concerned about al Shabaab and other offshoots of al Qaeda but not sure whether it has the ability to commit an attack in the United States.