Northwest Airlines plane on the tarmac at Amsterdam's Schiphol Airport

Dutch authorities say they are releasing all 12 passengers detained aboard a U.S. airliner that returned to Amsterdam Wednesday just after takeoff on a flight to India.

Officials announced the decision Thursday after determining that the incident was not terrorism-related. Officials detained and interrogated the 12 who were held for suspicious behavior.

Witnesses aboard the India-bound flight say the 12 raised concern when they began passing mobile telephones among themselves, and attempting to make calls as the Northwest Airlines DC-10 was taking off early Wednesday.

Authorities say the plane had just crossed into German airspace when the crew sounded the alert. Dutch fighters escorted the plane back to Amsterdam's Schiphol International Airport.

The flight was a little over half full, with 149 passengers. No injuries or disturbances were reported.

Wednesday's incident in The Netherlands came two weeks after British authorities announced that they had foiled a terrorist plot to blow up as many as 10 commercial flights bound for the United States.