The Russian plane that crashed in Egypt at the weekend "may well have been brought down by an explosive device", Downing Street has said, reports BBC.
All flights between the UK and Sharm el-Sheikh have been suspended on Wednesday evening as UK experts assess security at the Egyptian airport.
Number 10 said flights had been delayed as a "precautionary measure" after "more information has come to light".
Russian Airbus 321 crashed on Saturday, killing all 224 people on board.
"We would underline that this is a precautionary step and we are working closely with the airlines on this approach," a Number 10 spokesman said.