British Airways has cancelled all flights for seven days to Cairo amid fears over safety in the Egyptian capital.
In a statement the operator 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."
It is understood passengers were only told of the cancellation when they arrived at Heathrow airport for their flights.
Official Foreign Office advice, updated during Saturday on its website, reads: "There’s a heightened risk of terrorism against aviation.
"Additional security measures are in place for flights departing from Egypt to the UK.
"You should co-operate fully with security officials at airports."
Are you from Liverpool and your flight to Cairo cancelled? Email kate.mcmullin@reachplc.com
A spokesman for Cairo airport told the BBC the airport had yet to be notified by BA of any such changes.
Meawhile Lufthansa has also cancelled flights from Munich and Frankfurt into Cairo.
When asked for more details about why flights had been suspended and what security arrangements the airline was reviewing, a spokeswoman for British Airways responded: "We never discuss matters of security."
A letter was given to British Airways passengers - one of whom posted it on Twitter . The letter reads: "We are sorry to inform you that your flight from London Heathrow to Cairo has been cancelled.
"We constantly review 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 is safe to do so.
Official Foreign Office travel advice for Egypt was updated on Friday.
The Foreign and Commonwealth Office (FCO) advise against all travel to the Governorate of North Sinai, due to continuing criminal activity and terrorist attacks on police and security forces that have resulted in deaths.
The Foreign Office advises against all but essential travel by air to and from the Egyptian resort of Sharm el-Sheikh, but has not issued similar warnings against air travel to and from Cairo.
British Airways is one of two airlines flying nonstop between UK and Cairo - the other is EgyptAir whose flights are continuing as normal.
