The remains of a Russian airliner are seen at the crash site in Egypt's Sinai Peninsula, Nov. 1, 2015. More than 200 people perished in the crash, the cause of which remains under investigation. Reuters

Based on a preliminary analysis of information from flight data recorders (aka "black boxes") recovered from a Russian plane that crashed over the weekend in Egypt, a Russian airliner was not struck from the outside and the pilot did not make a distress call before the plane disappeared from radar, a source on the committee analyzing the data said Monday, Reuters reported. The Egyptian government said the black boxes were being examined by Egyptian and Russian experts as well as German and French specialists from Airbus and from Ireland, where the aircraft was registered.

An Airbus A321 carrying 224 people crashed Saturday in the Sinai Peninsula, killing everyone aboard. The cause of the crash remains uncertain and the investigation is continuing. Officials for the charter company that operated the aircraft have asserted that the plane and crew were faultless, and that the crash could have been caused by “an external impact on the plane,” but many officials have said it is too early to know for sure.

“Such a statement is premature and is not based on any real facts,” Alexander Neradko, head of the federal Air Transportation Agency, said on the Rossiya-24 news channel, the New York Times reported. “Much more work will have to be done on a detailed study of the plane’s constructive elements; flight recorders will have to be deciphered and analyzed.”

Despite the claims made by the source from the committee analzying the flight recorders, Neradko said, Egypt was keeping tight control over the data from the black boxes and other instruments.

“The Egyptian commission is conducting the investigation, and is giving no records and transcripts, be it of the flight recorders or on-ground recorders or radar data, to anyone,” said Neradko, the New York Times reported.

Amid a lack of information on what actually happened, the Islamic State group said its militants destroyed the aircraft to retaliate for the deaths of colleagues killed by Russia’s recent involvement in the Syrian conflict, however those claims have been unsubstantiated, the New York Times reported.