Romulus, Michigan (CNN) -- A Nigerian man is "talking a lot" to the FBI, said a senior U.S. official, after what the United States believes was an attempted terrorist attack on an inbound international flight. The initial impression is that the suspect was acting alone and did not have any formal connections to organized terrorist groups, said the senior official who is familiar with the investigation. The suspect, identified by a U.S. government official as 23-year-old Umar Farouk Abdulmutallab, ignited a small explosive device Friday, shortly before a Northwest flight from Amsterdam, Netherlands, made its landing in Detroit, Michigan. With the aid of the cabin crew, another passenger quickly helped subdue and isolate Abdulmutallab, passenger Syed Jafry told CNN.
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NEW: Nigerian in custody, "talking a lot," U.S. official says, after incident
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White House is considering the incident an attempted terrorist attack
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Passenger is immediately subdued; FBI investigating
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Flight originated in Amsterdam, Netherlands, ended in Detroit, Michigan
He did not undergo secondary security screening in @placeholder, an administration official said.