The White House's top counterterrorism adviser says the Secret Service's prostitution scandal did not expose weak spots in the president's security.

John Brennan says the disciplinary actions taken against the officers allegedly involved shows that Secret Service will take whatever action is necessary to ensure that potential threats won't get an opportunity to "penetrate the security shield that surrounds the president."

Eight Secret Service officers were fired and three others disciplined for their behavior in Colombia where they were setting up security for a visit by President Barack Obama.

The agency has issued new rules of conduct for its officers, including prohibiting entertaining foreigners in the officers' hotel rooms.

Brennan spoke Sunday on CNN's "State of the Union."