Britain's foreign secretary said on Sunday that airport security in many cities will need to be overhauled if it is confirmed the Russian plane crash in the Sinai was caused by a bomb planted by the ISIL terrorists or someone inspired by the militants.
Foreign Secretary Philip Hammond warned that if those suspicions are true, there needs to be a rethink of security at airports in areas where the extremist group is active.
He told the BBC Sunday that "may mean additional costs, it may mean additional delays at airports as people check in."
US and British officials suspect the October 31 flight from Sharm el-Sheikh to St. Petersburg was brought down by a bomb on board, but Egypt warns it is too early to say what caused the crash.
Investigators of the Russian plane crash in Egypt are "90 percent sure" the noise heard in the final second of a cockpit recording was an explosion caused by a bomb, a member of the investigation team told Reuters on Sunday.
The Airbus A321 crashed 23 minutes after taking off from the Sharm al-Sheikh tourist resort eight days ago, killing all 224 passengers and crew. ISIL terrorists fighting Egyptian security forces in Sinai said they brought it down.
A series of international airliners have suspended their flights to Egypt and evacuations of thousands of foreign nationals from the country are underway.
Russia has returned 11,000 of its tourists from Egypt in the last 24 hours, RIA news agency said on Sunday, a fraction of the 80,000 Russians who were stranded by the Kremlin's decision on Friday to halt all flights to Egypt.
Britain has also started flying out some of the 20,000 of its nationals estimated to have been in Sharm el-Sheikh at the time of the crash.
Nine flights carrying almost 2,000 people flew back to Britain on Saturday, after around 1,500 returned the previous day.
Airport officials said eight flights were bound from Sharm el-Sheikh to Britain on Sunday.
Flight numbers have been limited because both Russia and Britain have banned tourists from bringing their check-in luggage, which will be flown home separately.