Flights from Sharm el-Sheikh to the UK are being suspended tonight amid fears that a Russian plane was brought down by a bomb, Downing Street has announced.
The "precautionary" move is to allow time for a specialist British team to assess security arrangements in the Egyptian resort.
A Number 10 spokeswoman said: "While the investigation is still ongoing we cannot say categorically why the Russian jet crashed. But as more information has come to light we have become concerned that the plane may well have been brought down by an explosive device.
"In light of this, and as a precautionary measure, we have decided that flights due to leave Sharm for the UK this evening will be delayed.
"That will allow time for a team of UK aviation experts, currently travelling to Sharm, to make an assessment of the security arrangements in place at the airport and to identify whether any further action is required. We expect this assessment to be completed tonight."
Prime Minister David Cameron will chair a meeting of the Cobra emergency committee on the issue later.