- Russian planes have been bombing ISIS targets in Syria for about six weeks
- New video is five minutes long and the audio is in Russian
In the nearly five-minute long video, a chant in Russian is heard over visual compilations of old ISIS propaganda and generic video of Russian cities and buildings.
The video is entitled "Soon Very Soon the Blood Will Spill like an Ocean" and was posted two weeks after a Russian commercial jet crashed
in Egypt, killing 224 people
. An ISIS affiliate has claimed
it brought down the plane.
CNN has not independently verified the video is authentic, but it was posted on ISIS-affiliated social media accounts.
Russian security services are working to verify the authenticity of the video, the country's state news agency Sputnik reports.
Kremlin spokesperson Dmitry Peskov told reporters in Moscow: "I've read news about this video, but have not seen it myself. I don't know the authenticity of this video, and I don't know the authenticity of these sources.
"But in any case I'm sure this material will be subject of scrutiny by our special services."
Russian air power has backed the Syrian leader Bashar al-Assad's military in its fight against ISIS since October 1. While Russian officials have said their airstrikes target ISIS, U.S. officials have said some have not been in areas where the terror group is operating.
Russia has no wish to see Syria become a radical Islamist state or a long-term safe haven for terror groups, with possible consequences for its own Muslim regions in the Caucasus. It is "also concerned about the possible return to Russia of the 2,000 or more Russian-speakers currently fighting against Assad's forces," Nikolay Kozhanov of the Carnegie Moscow Center said last month.
ISIS has threatened Russia before, even prior to Moscow's military support in Syria.