A noise was heard in the last second of the cockpit voice recording of the Russian plane that crashed in Egypt's Sinai region, killing 224 people.

The head of the Egyptian team investigating the fatal crash told a news conference in Cairo that analysis of the noise is under way to identify its nature.

Ayman el-Muqadem said the way the debris was scattered over a wide area indicated the Airbus plane broke up mid-air, but initial observations do not shed light on what caused it.

US and British officials have cited intelligence reports as indicating that the Russian flight from Sharm el-Sheikh to St Petersburg was brought down on October 31 by a bomb on board.

Earlier, Egypt's foreign minister complained that Western governments had not sufficiently helped Egypt in its war on terrorism and had not shared relevant intelligence with Cairo.

Sameh Shoukry said that "European countries did not give us the co-operation we are hoping for".

Egypt's past calls for assistance and co-ordination on terrorism issues from "the countries that are now facing the danger" had not been dealt with seriously, he said.

Mr Shoukry also complained that Western nations that have suspended flights to Sharm el-Sheikh did not share with Cairo the relevant intelligence upon which they based their decisions.

Mr Shoukry told reporters that Egypt "expected that the information available would be communicated to us instead of being broadcast" in the media.

The foreign minister's comments came as Egypt launched an investigation into the staff and ground crew at the Sharm el-Sheikh airport, according to Egyptian airport and security officials.

The officials said that authorities were questioning airport staff and ground crew who worked on the Russian flight and had placed some employees under surveillance.

The crash one week ago dealt another blow to Egypt's battered tourism sector, which is yet to fully recover from years of political turmoil. Russians comprise nearly a third of all tourists who visited Egypt in the past year.

Islamic State extremists have claimed that they brought down the Russian Metrojet flight, with mostly Russian tourists onboard, though they did not offer any proof.

Egyptian authorities have been trying to whip up support for a war on terror after the military overthrow of Islamist President Mohammed Morsi in 2013.

A crackdown on Islamists and a series of militant attacks on security buildings and checkpoints, mainly in the restive Sinai Peninsula, have followed Mr Morsi's ousting, with a Sinai-based affiliate of the Islamic State group claiming responsibility for some of the most devastating attacks.

On Friday evening, Russia suspended all flights to Egypt, joining the UK, which had specifically banned all flights to Sharm el-Sheikh.

Ireland has also suspended flights to the Red Sea resort, while at least a half-dozen Western European governments told their citizens not to travel there.

Empty charter planes have been flying to Sharm el-Sheikh to bring home stranded Russian and British tourists. But these flights banned passengers from checking in luggage - reflecting an apparent concern about security and luggage-screening procedures at the airport.

Tourism chief Oleg Safonov said, according to Russian news agencies, that a revised count showed 80,000 Russians are currently in Egypt - 79,000 of them in the resort areas of Hurgada and Sharm el-Sheikh.