Police removed an airline passenger Sunday following a disruption on the same Detroit-bound flight that was subject to a failed bomb attack on Christmas Day.
An FBI spokeswoman in Detroit said Sunday's incident turned out to be nothing serious.
"Today (Sunday) at Detroit Metro Airport, the Joint Terrorism Task Force (JTTF) responded to a report from an incoming flight from Amsterdam where a passenger spent a lengthy time in the restroom. This raised concerns so an alert was raised. JTTF investigated and the investigation shows that this was a non-serious incident and all is clear at this point," the FBI spokeswoman told Fox News.
A law enforcement official said the man removed from a Sunday flight to Detroit posed no security risk to the plane.
The official says the passenger was taken into custody after becoming verbally disruptive on landing. Subsequent interviews by investigators determined he was a businessman who became ill during the flight.
A source confirmed this report to Fox News, saying the passenger was indeed sick and that the incident appears to be "a non-event at this point."
Authorities did not find any sign of explosives.
A federal law enforcement official said the man, who was from Nigeria, was interviewed by authorities and the aircraft was swept. But the official said the incident was all an incredible coincidence.
DHS Press Secretary Sara Kuban issued a statement on the incident: "A passenger on today's Northwest flight 253 from Amsterdam to Detroit spent an unusually long time in the aircraft lavatory. Due to this unusual behavior, the airline notified TSA and the agency directed the flight to taxi to a remote area upon landing to be met by law enforcement and DHS."
"The passenger in question, a Nigerian national, was removed from the flight and interviewed by the FBI; indications at this time are that the individual's behavior is due to legitimate illness, and no other suspicious behavior or materials have been found."
"Though this does not appear at this time to be a security incident, in an abundance of caution, the aircraft was fully screened, with negative results, and all baggage is being rescreened before the aircraft taxis to the gate."
Several police vehicles and a police command unit had surrounded a Northwest Airlines plane at Detroit's Metro Airport Sunday after the pilot on the flight requested emergency help. The passenger reportedly became verbally disruptive and barricaded himself in the bathroom for an hour.
Two sources tell Fox News that the suspect boarded a plan in Lagos, Nigeria, with no baggage, and said the FBI has already sent an e-mail alert to other federal agencies notifying them of the incident.
A source told Fox News that the man taken into custody at the Detroit airport was a Nigerian national in his 30s. Federal officials know who the suspect is, but won't provide any more details.
Detroit's Metro Airport spokesman John Wintner said there was a report of suspicious activity on the Delta/Northwest Airlines Flight 253 from Amsterdam Sunday. That is the same flight that Umar Farouk Abdulmutallab, a 23-year-old Nigerian man, was suspected of attempting to blow up over Detroit on Christmas Day.
White House spokesman Bill Burton said President Obama was notified of the disturbance Sunday as federal officials began reviewing airline security measures.
"The President was notified shortly after 9:00 a.m. Hawaiian time of the incident regarding an unruly passenger on the flight arriving in Detroit by NSS chief of staff Denis McDonough," Burton said.
"The President stressed the importance of maintaining heightened security measures for all air travel and gave instructions to set up another secure teleconference briefing as soon as possible."
All 257 passengers and 12 crew were deplaned safely, said Delta spokeswoman Susan Elliott. The flight landed in Detroit at 12:34 p.m. Sunday.
The plane was moved to a remote location at the airport so authorities can conduct additional screening, Reuters reported.
Fox News' Mike Levine and The Associated Press contributed to this report.