Doubts over the possible causes behind the crash of the Kogalymavia airplane in Egypt's Sinai peninsula last week remain as different suggestions have been expressed by the Russian airline, investigators, authorities and intelligence sources.

According to French aviation officials familiar with the investigation, the crash was not due to technical failures, the BBC reports.

Other French officials said that the flight data recorder suggested that a "violent, sudden" explosion caused the crash.

According to British officials, intercepted militant calls indicated that a bomb had been put in the hold before take-off.

Militants affiliated to Islamic State (IS) have claimed responsibility for taking down the airplane.

However militants in North Sinai, where the crash occurred, have not revealed how they had taken down the aircraft.

French air accident investigators said that the flight data recorder had shown that "everything was normal during the flight, absolutely normal, and suddenly there was nothing".

Frenchmen are involved in the investigation as the crashed aircraft was manufactured by Airbus, which is based in France.

An unnamed US official said on Friday that communication has been intercepted between IS officials in Syria and affiliates in Sinai about downing of the aircraft.

Earlier in the week, US and British intelligence sources had similarly suggested that the airplane might have been bombed, but Russia and Egypt had called for more caution over such theories.

On Friday, Russian President Vladimir Putin ordered the suspension of all Russian flights to Egypt and the evacuation of 50 000 Russians currently on holiday in Egypt.

In a telephone conversation, Putin and Egyptian President Abdel Fattah el-Sisi agreed to continue active cooperation in the area of flight safety.

Several other countries, such as the UK, the Netherlands and Belgium, have suspended flights to Sharm el-Sheikh.

The Airbus A321 operatd by Russian airline Kogalymavia was conducting flight 9268 between the Egyptian resort of Sharm el-Sheikh and Saint Petersburg when it crashed in North Sinai shortly after take-off on October 31.

None of the 224 people on board the airplane, among whom were 217 passengers and seven crew members, survivied the crash.

For the time being, Russia has no evidence confirming that the crash was caused by explosion on board, TASS news agency informs.

Russian specialists will ask French and Egyptian investigators to provide evidence confirming the onboard explosion.

At present, it was too early to conclude the exact nature of the noises and whether these indicated explosion.

Earlier in the week, representatives of Kogalymavia blamed the crash on midair mechanical impact.

Russian officials have refrained from making any suggestions on the likely causes of the crash until first results from the investigation become available.