CAIRO (AFP) - Egyptian President Abdul Fattah al-Sisi has dismissed as "propaganda" claims by a branch of the Islamic State in Iraq and Syria (ISIS) that they were responsible downing a Russian plane, the BBC reported on Tuesday (Nov 3).

His remarks came as a top US intelligence official said it was "unlikely" that ISIS had been involved in the Metrojet airline disaster over the Sinai peninsula that killed 224 people on Saturday.

"When there is propaganda that it crashed because of ISIS, this is one way to damage the stability and security of Egypt and the image of Egypt," Sisi told the BBC.

"Believe me, the situation in Sinai - especially in this limited area - is under our full control," he added. "All those interested in the matter are welcome to participate in the investigation."

Experts say the fact that debris and bodies were strewn over such a wide area points to mid-air disintegration of the aircraft.

On Monday, US Director of National Intelligence James Clapper said he could not rule out ISIS involvement in Saturday's incident, but thought it "unlikely".

"We don't have any direct evidence of any terrorist involvement yet," he said.

Earlier the airline said the plane had come down due to "external" factors and ruled out any technical failure or human error in the disaster.

"The only explanation is some kind of external action," senior Kogalymavia executive Alexander Smirnov told a news conference in Moscow, without elaborating.

However, Alexander Neradko, head of Russia's aviation authority, criticised the airline's comments, saying they were "premature and not based on any real facts".

Analysis of the plane's "black boxes", which could solve the mystery of what happened to the doomed jet, is expected to begin on Tuesday, according to Egyptian officials.

Analysts have dismissed claims that the jet could have been shot down by ISIS-affiliated groups in the region if it was flying at its cruising height of 30,000 ft (9,000 m), but did not rule out that a bomb may have been planted on board.