A United Airlines flight from Rome to Chicago was diverted to Ireland after a note was found in the aircraft’s lavatory, a source with knowledge of the incident said.
United flight 971, which departed from Rome just after 10:30 a.m. local time, was scheduled to land at O'Hare International Airport at around 2 p.m. CST.
After roughly four hours in the air, the flight was diverted to Shannon Airport in Ireland "following a potential security concern," United Airlines said in a statement. Police said the plane was diverted after the discovery of a message.
"Additional security screenings will be performed on all customers and baggage, and we will work to get customers on their way to Chicago as quickly as possible," the airline’s statement continued.
Passengers will stay in Shannon overnight and return to the U.S. Tuesday, United Airlines told NBC News.
All passengers had disembarked from the aircraft and the people and plane were being searched Monday afternoon.