One U.S. intelligence official told The Daily Beast that Moscow likely taken the decision to directly intervene in the four-and-a-half-year civil war following opposition gains, contrary to what Vladimir Putin told reporters last week—that any such talk was “premature.”

“Russia’s military involvement raises a number of concerns, especially because it does not appear to be coordinated with the other countries operating in the area,” the official said. “It is not clear what Russian intends to actually do. However, Russia has generally not exercised restraint in military confrontations.”

A oft-cited fear in the U.S. is that Russia won’t target ISIS, or only ISIS, but also Free Syrian Army rebels who may be working with the CIA or Pentagon.

But what’s most interesting about this news isn’t that Putin has unilaterally decided to rescue his embattled client in Damascus—it’s the kind of Russian troops he’s using to do it. Some of them are from the same units that spearheaded Russia’s year-and-a-half-long dirty war in Ukraine, which may now be in abeyance.