A United Airlines plane bound for Spain from Newark Liberty international airport turned around mid-flight on Saturday due to a possible security threat.

That came one day after another United Airlines flight bound for Minneapolis from Chicago was diverted to Madison, Wisconsin, on Friday because an unruly passenger evidently tried to breach the cockpit.

Saturday’s flight departed at about 6pm for Palma de Mallorca, Spain, but landed back at Newark Liberty at 9.37pm, according to the airport’s operator, the port authority of New York and New Jersey.

The airline said there were 190 passengers and 12 crew members onboard 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 of them remained on. The flight turned around after communicating with the airline’s headquarters in Chicago.

Passengers had to evacuate as port authority police swept the aircraft. Transportation Security Administration (TSA) and Customs and Border Protection (CBP) officers re-screened passengers before boarding again.

The airline declined to provide specifics on the cause of the incident.

Passengers boarded a replacement flight with a new crew, which took off early on Sunday morning and landed in Palma in the afternoon.

That was at least the third major aviation episode involving a United Airlines flight in four weeks.

On 3 May, an airline flight landing at Newark Liberty struck a light pole and a delivery truck, according to authorities. The truck’s driver had minor injuries. No one else was reported hurt.

Guardian staff contributed reporting