A flight travelling from Rome to Chicago was forced to make an emergency landing after a note, which reportedly made reference to a bomb, was discovered in one of the plane's toilets.
The United Airlines flight UA971 made an emergency landing in Ireland on Monday.
Passengers on the flight have had to offer samples of their handwriting to police who are investigating the incident.
The Irish Times revealed that the note was reportedly scrawled onto the surface of one of the toilets.
United Airlines Boeing 767-322 #UA971 flight from Rome to Chicago was diverted to Shannon Airport in Ireland on Monday after a hand writing message referred to a bomb on the plane was discovered on board pic.twitter.com/VmmuUCpxDV— Manu Gómez (@GDarkconrad) June 11, 2018
The plane was carrying 214 passengers and crew when it safely landed at Shannon Airport.
Irish police immediately searched passengers and their hand baggage while handwriting samples from each person were handed over to authorities.
Luggage in the cargo was also examined by police.
The United States government is also investigating the incident, comparing the handwriting on the toilet to similar written threats that have been left on aircrafts, reported Reuters.
United Airlines said the plane was diverted due to “a potential security concern”.
“After assessing the situation, our crew made the decision to divert to the nearest available airport,” a statement from the airline read.
“Additional security screenings will be performed on all customers and baggage.”