LONDON - British fighter jets escorted an EgyptAir plane bound for New York to a Scottish airport on Saturday after a note was found on board threatening to set it on fire, authorities and eyewitnesses said.

"An EgyptAir aircraft flying from Cairo to New York was diverted to Prestwick Airport after a suspicious note was discovered on the aircraft," said a statement from Police Scotland. The force later said that all 326 passengers had been taken off the plane and that officers were conducting an extensive search of the aircraft.

Britain's Ministry of Defence confirmed that Typhoon aircraft had been scrambled from Royal Air Force base Leuchars in Scotland following an incident on board a passenger plane.

An eyewitness told the BBC that two jets had escorted the passenger plane to Prestwick, near Glasgow. The aircraft taxied to a secluded area of the airport where it was surrounded by 10 to 15 police vehicles.

Britain is on high alert as world leaders including US President Barack Obama and Russian President Vladimir Putin converge on Northern Ireland for the G8 summit, which begins on Monday.

The alarm was raised when a passenger, BBC New York producer Nada Tawfik, said she told plane crew that she had found a note in the toilet sink that read "I'll set this plane on fire."

Tawfik told the broadcaster that the message was scrawled in pencil on a napkin and that it also pinpointed a seat number.

"It almost looked like a child's handwriting or someone who has very sloppy handwriting, but it was very alarming especially these days when everyone is so concerned about safety on flights," she said.

"I said to one of the stewardesses 'I don't know if this is a prank', they said 'no, it can't be a prank'.

"Either someone has a very bad sense of humour or, you know, it's very scary.

"As you can imagine, it's a pretty tense situation.

"Everyone's trying to grab what they can to drink, people are concerned, there are babies on board who are all getting very frustrated," she added.

Prestwick airport said in a statement that there had been no disruption to scheduled flights.

Prestwick airport, on the southwest coast of Scotland, and is one of the last places planes can land, if necessary, on the transatlantic route from Europe to North America.