Egypt has found and obtained both black boxes from a Russian passenger plane that crashed in the country's Sinai peninsula on Saturday, the civil aviation minister told a news conference.

There are normally two black boxes on an aircraft, one for cockpit voice recordings and one for flight data. Egyptian authorities had earlier said they only found one.

Meanwhile, Russia's Investigative Committee said it was checking fuel samples from the last refueling stop, in the Russian city of Samara, of an airliner that crashed in Egypt, RIA news agency reported citing the committee's spokesman.

The spokesman, Vladimir Markin, also said investigators are questioning people who were involved in preparing the aircraft and its crew, and carrying out searches at Moscow's Domodedovo airport where the airline that operated the plane is based. The committee said it had opened a criminal case against the airline.

Meanwhile, United Nations Secretary-General Ban Ki-moon has condemned the alleged attack on a Russian plane in "the strongest terms" and voiced his deep sadness for the victims of the crash in Egypt's Sinai earlier on Saturday.

Ban told a group of journalists in Geneva that he has received the report that the Islamic State (IS) claimed responsibility for the crash of a Russian plane, saying it is a complete crime to target civilian airlines and a full investigation should be carried out as soon as possible.