Janet Napolitano 'No indication'

US President Barack Obama's top security official said Sunday there was "no indication" an accused Nigerian terrorist was acting as part of a larger plot when he tried to blow up a US-bound flight on Christmas Day.

"Right now we have no indication it's part of anything larger, but obviously the investigation continues," US Homeland Security Secretary Janet Napolitano told CNN, referring to the thwarted attack on a Northwest jet by suspect Umar Farouk Abdulmutallab, 23, as the plane approached the city of Detroit, Michigan.