British Airways has suspended its flights to Cairo for security reasons.
The UK airline said flights to and from the Egyption capital would be cancelled for the next seven days "as a precaution."
Lufthansa also announced a suspension; however, the German operator has now resumed its flights.
In a statement, BA 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."
A BA spokeswoman refused to give any further details about the decision and said: "We never discuss matters of security."
The spokeswoman later added: "We are rebooking customers who wish to travel this week on flights with alternative airlines. Customers who no longer wish to travel will be offered a refund."
It is understood BA made the Department for Transport aware of its decision before it made the announcement.
A UK Government spokesman said: "We are aware that British Airways is notifying passengers that it has decided to suspend flights to Cairo temporarily."
The Egyptian Civil Aviation Ministry said it is in touch with the British embassy which told Egyptian officials it did not take the decision.
It added that it will increase the number of flights to London from Cairo, as well as use a new Boeing 787 "to facilitate the travel of passengers" during the seven-day period.
According to Reuters, which spoke to three Egyptian sources, British staff had checked security measures at Cairo airport on Wednesday and Thursday.
BA said its passengers who were due to fly to the Egyptian capital on Saturday night were issued with letters informing them of the airline's decision.