More than 200 Russian Mercenaries were killed by coalition forces?

Thanks to Matthew for the link!

via Daily Beast.

Hundreds of Russian mercenaries were reportedly killed by U.S. forces in a failed attack on a U.S.-held military base and refinery last week. Citing U.S. and Russian sources, Bloomberg News reported more than 200 contract killers—mostly Russian citizens fighting for Syrian President Bashar al-Assad—died in what is believed to be the deadliest incident between Russian and U.S. citizens since the Cold War. Russia’s military has disowned any responsibility for the attack in the Deir al-Zour region and a U.S. military spokesperson appeared to accept that claim in a statement. No U.S. coalition casualties have been reported from the attack, but the death toll from the mercenary side is still rising, with soldiers being treated in hospitals in Moscow and St. Petersburg. Defense Secretary James Mattis is reported to have called the incident “perplexing.” The reported death toll would be far greater than all of the Russian casualties the Kremlin has acknowledged during its Syrian incursion.

This is curious.

I haven't heard a word of protest or anger from the Russians, the US is playing it very cool and saying that they were in contact with their Russian counterparts during the fighting....and everyone is acting like its a non-issue.

Did they clean out their prisons or are these homegrowns that were recruited for cannon fodder in Syria?