India, June 1 -- A United Airlines flight bound for Spain from US' Newark Liberty International Airport turned around mid-flight Saturday due to a possible security threat in flight.

The flight departed around 6 pm for Palma de Mallorca, Spain, but landed back at Newark at 9:37 pm, according to the Port Authority of New York and New Jersey.

The airline said there were 190 passengers and 12 crew members on board the Boeing 767 aircraft.

According to air traffic control audio, security came to inspect the aircraft after someone named their Bluetooth device a "certain four-letter word." A passenger posting on social media said crew members repeatedly asked passengers to turn off all Bluetooth devices, but two devices remained on.

The fli...