A statement from Downing Street, the office of British Prime Minister David Cameron, says the Metrojet Airbus A321 that crashed in Egypt over the weekend "may well have been brought down by an explosive device."
It added that Britain-bound flights from the resort area of Sharm on Egypt's Sinai Peninsula would be delayed to allow for additional security screening.
"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," the statement said. "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."
On Tuesday, US media had reported that a "heat flash" had been detected by an infrared satellite over the Sinai Peninsula at the time of the crash.
This comes as Egypt's Civil Aviation Ministry released a statement on its Facebook page with an update about the black box analysis from the crash of the Metrojet Airbus A321 on Saturday.
The statement said the data from the flight data record had been extracted and validated, and would now be subject to investigation by investigators. The information contained on the cockpit voice recorder will not be so straightforward to analyze.
"The Cockpit Voice Recorder (CVR) is partially damaged and a lot of work is required in order to extract the data from it," the ministry said. "Consequently, no further comment on the content of the CVR can be made."
The plane crashed shortly after taking off from a resort on the Sinai Peninsula in Egypt on its way to St. Petersburg, Russia. All 224 passengers on board were killed. Russian investigators have identified 33 of the victims.
Authorities have not yet conclusively determined the cause of the crash, which left debris strewn over a wide area. Emergency Situations Minister Vladimir Puchkov said investigators had expanded the search area in Egypt from 30 square kilometers (18.6 miles) to 40.
Shortly after the crash, a group affiliated with the "Islamic State" (IS) terrorist group claimed responsibility, though Russian, Egyptian and American officials have cast doubt on the possibility of the plane having been destroyed by a missile launched from the ground. IS repeated the claim that they were responsible for the attack on Wednesday.

mz/rc (Reuters, AFP)