(AP) - A commercial passenger jet carrying cargo fromYemen landed in New York under military fighter-jet escort and itscargo was searched Friday, as parcels in transit across the globewere scrutinized after authorities overseas found two explosivepackages from Yemen bound for Chicago.

No explosives were found aboard Emirates Airlines Flight 201after a search, FBI spokesman Richard Kolko said. He said the planeflew in to John F. Kennedy Airport under escort as a precaution.

President Barack Obama called the coordinated attacks a"credible terrorist threat." Packages were found aboard cargoplanes in Dubai and England and U.S. officials said they wereincreasingly confident that al-Qaida's Yemen branch wasresponsible.

The Emirates Airlines plane, a Boeing 777, landed shortly after3:30 p.m. Passengers walked off the jet on two covered stairwaysand onto the tarmac, dragging their luggage behind them. Severalpolice cars surrounded the airliner.

The flight crew didn't mention any issue with cargo, passengerssaid. They were told there was a heightened security concern andthat their bags would be searched but weren't told why. They alsodidn't know about the interest in their aircraft until they saw iton TV screens in the airport and glimpsed the mob of waitingreporters.

"We saw a lot of police and they instructed us that we would begetting on a bus. And that all our luggage would again bescreened," said Nick Chan, 32, who was returning to Manhattan froma business trip.

David Packles, a 23-year-old financial analyst returning from avacation to Thailand, said he hadn't noticed fighter jets tailingthe plane and didn't think the 20 extra minutes they spent on thetarmac was that unusual.

"It's a 14-hour flight. Everyone was just kind of exhausted,"he said.

Emirates said in a brief statement that it was "cooperatingfully with the U.S. authorities" and would provide moreinformation as soon as it was available.

U.S. fighter jets routinely escort airliners when there may be aproblem in order to observe the aircraft and be prepared to takeany action if necessary.

John Cornelia, a spokesman for U.S. North American AerospaceDefense Command, said the Emirates airliner was escorted by aCanadian fighter based in Bagotville, Quebec, to the U.S. border,where two U.S. fighters from the Barnes Air National Guard Base inMassachusetts took over.Go to iO Extra on Channel 612 to watch Chopper 12 footage of the fighter-jet escort at John F. Kennedy International Airport.Terror plot thwarted as U.S.-bound explosives seized