Sisi, Cameron agree tight security needed at Sinai airport

Egypt's president and Britain's prime minister have agreed on the need for "the tightest possible security" at the Sinai resort airport where a doomed Russian airliner departed, according to a statement from Cameron's office released late on Tuesday.

Abdel Fattah al-Sisi and David Cameron spoke by telephone ahead of the Egyptian leader's arrival in London for his visit this week. 

Their statement came as state media reported that at least three Egyptian policemen were killed when a suicide bomber rammed his vehicle into a police club in North Sinai provincial capital El-Arish early on Wednesday.

The Islamic State's Sinai affiliate claimed that one of its militants had carried out the attack.

Investigators have yet to determine the cause of the crash in Sinai on Saturday which killed all 224 people on board the Kogalymavia Airbus A321 that had set off from Sharm el-Sheikh, a popular destination for British tourists.

The Islamic State (IS) group's branch in the Sinai Peninsula claimed it downed the plane, but the group provided no details and experts say other possibilities include a mechanical failure that caused the plane to disintegrate in mid air.

Cameron and Sisi "agreed it was important not to pre-judge the investigation," the British statement said.

They "noted that there was still uncertainty about the cause of the crash and agreed it would be prudent to ensure the tightest possible security arrangements at Sharm el-Sheikh airport as a precautionary measure."

Some aviation experts have suggested that a bomb could have been placed on board before take-off.

Egyptian state media said on Wednesday that Sisi had set off for his three-day visit to Britain.

Investigators began on Tuesday examining the black box flight recorders retrieved from the crash site, as Sisi warned the investigation could take a long time.