President Warns of 'Credible' Threat

President Obama comments on the two suspicious packages, originating in Yemen, found on cargo flights to the United States.

Mail bomb videos:
Brennan: Mail Bombs Bear al-Qaeda's Hallmarks

GOP's King: Administration Handled Yemen Plot Perfectly

White House official: Airplane Bombs Were From al Qaeda

Brennan Says Cargo Plane Explosives Could Detonate on Their Own