The cancellations started on Saturday (20 July). BA is yet to specify what the security concern is.
Passengers due to fly to Cairo on Saturday were handed a letter informing them their flights had been cancelled.
"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," said BA in a statement.
The letter to passengers added: "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."
