LONDON (AFP) - 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.

"At around 1420hrs today (1320GMT) 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 explained that more than 100 passengers had been let off the plane and that the remainder "continue to disembark in a calm and orderly manner".

"The passengers are being taken to the airport terminal where they are being looked after by aircraft staff," added the statement.

Officers will interview all the passengers during the evening and there were no reports of any injuries, police said.

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

An eyewitness told the BBC that two jets escorted the passenger plane to Prestwick, near Glasgow, and that the craft was surrounded by 10 to 15 police vehicles in a secluded area of the airport.

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.

Police Scotland confirmed officers were responding to an ongoing situation while the airport issued a statement on its website saying it was "currently dealing with an incident".

It added there was no disruption to scheduled flights.

Air traffic control said it had followed standard procedure after being alerted there was "a problem" with the flight.

The tracking service FlightAware showed the plane was making progress over the North Sea before it abruptly changed direction and headed to Prestwick.

The airport is 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.