Egypt says its experts are being joined by teams from Russia and also the Republic of Ireland, where the Airbus 321 was registered.

It crashed over the Sinai peninsula, killing all 224 people on board.

Egypt dismissed as "propaganda" claims that militants linked to Islamic State (IS) brought down the aircraft.

President Abdul Fattah al-Sisi told the BBC that it was too early to say what had caused the crash.

The aircraft - flying from Sharm el-Sheikh to St Petersburg - is thought to have broken up in mid-air.

Egypt's Civil Aviation Minister Hossam Kamal said the investigators would conclude their last field inspection at the crash site on Tuesday and start working on the two flight recorders, or "black boxes".

Mr Kamal was quoted by the Associated Press news agency as saying that it "will take some time" to produce the final report and that the joint investigative committee "has all the tools and experts to deal with the investigation".

The experts hope the examination of the recorded onboard conversations as well as flight data will help provide clues as to what caused the crash.

On Monday, Russia's Kogalymavia airline blamed "external influence" for the crash of its plane. But the head of Russia's aviation agency said such talk was premature and "not based on any proper facts".

Meanwhile, Russia's Interfax news agency on Tuesday quoted a source as saying the plane's cabin crew had not had any information about faults before the moment of crash.

"According to the recording of the conversations between the cabin crew and flight operations officers, the situation onboard four minutes before the aircraft disappeared from the radars was normal, the crew had regular conversations with flight operations officers," the source said.

During his BBC interview, President Sisi warned against jumping to conclusions.

"When there is propaganda that it crashed because of Isis [IS], this is one way to damage the stability and security of Egypt and the image of Egypt," he said.

"Believe me, the situation in Sinai - especially in this limited area - is under our full control."

Militants launched an insurgency in the Sinai following the fall of President Hosni Mubarak in 2011. They stepped up their attacks after the military overthrew Islamist President Mohammed Morsi in mid-2013.

A year ago, the insurgents renamed their movement Sinai Province and pledged alliance to IS. Hundreds of police and soldiers have been killed.

After the crash, Sinai Province issued a written statement and an audio message saying that it brought down the passenger jet.

However, experts doubt it possesses the weapons capable of bringing down an airliner.

Source: BBC