The Russian airplane crash site on the Sinai Peninsula is pictured in this handout photo satellite image provided by Russian Emergencies Ministry on November 1, 2015.  [Photo/Agencies]

The intelligence regarding the IS is in part based on monitoring of internal messages of the terrorist group, another US official said.

Those messages are separate from public IS claims of responsibility, that official said.

Sinai Province, a militant Egyptian group affiliated with the IS, claimed responsibility for Saturday's downing of the Russian plane through a statement. The group has been active in Sinai fighting with Egyptian security forces.

But the claim has not been verified by Egyptian and Russian officials.

US intelligence officials told the media Monday that infrared US satellite detected a heat flash at the same time and vicinity over the Sinai peninsula where the plane crashed, suggesting an mid-air explosion.