Egypt plane crash investigators "90% sure" the explosion heard on the black box recording of the Russian flight was a bomb, a member of the investigation team told Reuters.
A memorial service for the 224 victims of the crash was be held in St Petersburg today.
A British aircraft carrying 189 passengers had a near-miss with a military missile when landing at Sharm el-Sheikh airport just over two months ago, it has emerged.
The incident has come to light as British tourists in the Egyptian resort begin to return home following the grounding of flights amid security fears.
Reports of the incident say the Thomson aircraft had to take evasive action but landed safely. Thomson reported the incident to the Department for Transport.
A UK government spokesperson told ITV News: "We investigated the reported incident at the time and concluded that it was not a targeted attack and was likely to be connected to routine exercises being conducted by the Egyptian military in the area at the time."
A spokesman for Tui, which owns Thomson, added: "The view at the time was that it was probably a flare. As a result there was no cause for concern."
Terrorists would be able to bypass the wand-like devices being used to scan luggage in Sharm el-Sheikh, an expert has claimed.
Intelligence showed a "significant possibility" that the crashed Russian passenger jet was brought down by an explosion, ITV News was told.
As flights from Sharm el-Sheikh to the UK are delayed over bomb fears, we review what is known about the Egyptian plane crash tragedy.