Passengers at London Heathrow were handed letters from BA explaining the suspension of the Cairo flights
British Airways has cancelled all flights to the Egyptian capital Cairo for a week as a security "precaution".
Passengers about to board a BA flight to the city from London's Heathrow Airport were told that it was cancelled - and that there would be no alternative flights for a week.
The airline did not specify what the security issue was.
A spokesman for Cairo airport told the BBC the airport had yet to be notified by BA of any such changes.
A BA spokesman said: "We constantly review our security arrangements at all our airports around the world, and have suspended flights to Cairo for seven days as a precaution to allow for further assessment.
"The safety and security of our customers and crew is always our priority, and we would never operate an aircraft unless it was safe to do so."
German airline Lufthansa also cancelled flights to Cairo on Saturday. However, flights to the city would resume on Sunday, a spokesman said.