A United Airlines flight from Rome to Chicago diverted to Ireland due to a "potential security concern," the airline said Monday.
United said passengers aboard flight 971 and their luggage will be screened again "and we will work to get customers on their way to Chicago as quickly as possible."
Local police said passengers and the plane are being searched.
The diversion occurred after a threatening note was found on board, according to a person familiar with the matter. Police confirmed that a message was discovered but did not immediately respond to a request for more detail.
United declined to comment on the reason for the diversion. The plane, a Boeing 767-300, had 207 passengers and 11 crew members on board, United said.
Passengers will return to Chicago on Tuesday and the airline is working to get passengers overnight accommodations, United said on Twitter.
This story is developing. Please check back for updates.