An Alitalia flight from Milan to Boston has been diverted to the US state of Maine - the second European flight to be hit by a security alert in a week.
US officials say the name of a passenger on the flight matched that of someone on the US no-fly list.
An Air France flight from Paris to Boston was diverted to Maine on Thursday because a passenger was named on the same terror watch list.
Officials said they would meet the Alitalia plane in the city of Bangor.
The Air France plane was also ordered to land at Bangor airport last week.
After the unscheduled stop, the plane continued to Boston without the passenger who sparked the alert and three of his family members.
The passenger had almost the same name and birthdate as a person on the government's list of suspected terrorists, the Associated Press news agency said.
He was held by immigration officials, but later released.