A flight from London to Washington DC has been diverted to Boston after the pilot declared an emergency because of a "passenger disturbance". United Flight 923 from Heathrow Airport, with 182 passengers aboard, landed at Logan International Airport.
At least one passenger is reported to have been involved in a confrontation with the crew on board the flight.
An airport spokesman told the BBC that all passengers and crew were now safely off the plane.
State police are said to have taken control of the plane after it landed.
'Banned item'
Phil Orlandella, a spokesman for Logan International Airport, said the flight was escorted to Boston by two fighter jets.
"There was a supposed confrontation on board," he said.
"There may have been a banned item on board and they are now searching the luggage."
The flight was diverted due to the behaviour of one unruly woman, the Department of Homeland Security said.
An airport spokesman was quoted as saying she was carrying a screwdriver, matches, Vaseline and a note referring to al-Qaeda - but this was subsequently denied.
Security and sniffer dogs have been searching the luggage from the flight, which have been laid out on the tarmac at the airport.
