A plane flying from Europe to the US has been diverted after a cryptic note hinting at a bomb was reportedly found scrawled on the wall in the aircraft's bathroom.

The airline has confirmed that the reason for the unexpected diversion to Shannon airport was due to a "potential security concern".

Passengers on board United Flight 971 have disembarked from the plane and both checked and hand luggage is being re-screened.

#BREAKINGNEWS United Airlines flight UA-971 w 214 aboard was travelling fr Rome’s to Chicago diverted to Shannon after ‘bomb threat’ message found in toilet pic.twitter.com/xg5G4Ip75R

— Saji Assi (@assi_saji) June 11, 2018

The crew declared a May Day at around 12.45pm and informed air traffic controllers that they wished to divert to Shannon Airport.

Shannon airport implemented emergency procedures which involved alerting the local authority fire service, HSE National Ambulance Service and An Garda Síochána.

Reuters: United flight 971 en route from Rome to Chicago, diverted to Shannon, Ireland following 'potential security concern'

— Jesse Rodriguez (@JesseRodriguez) June 11, 2018

The flight's 214 passengers were removed from the plane, and sent to a nearby hotel.

"We will work to get customers on their way to Chicago as quickly as possible," United said in a statement.

According to the Irish Times, gardai are taking handwriting samples from passengers to try and establish who is behind the note.

Hello, Don. UA 971 canceled in Shannon. Customers and crew will be receive assistance with overnight accommodations and will arrive into Chicago on June 12th. Rebooking for customers with connections beyond Chicago is currently underway. ^TY

— United Airlines (@united) June 11, 2018

This story is developing, stay with us for more information.

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