Nusra FrontImage copyrightAP
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Russia says the al-Nusra Front is one of its targets
Indeed, as Mr Kofman says, the arrival of more attack helicopters means "Russia's military presence has expanded to several bases, since helicopters need forward operating bases to fly from".
US and other sources have detected Russian artillery units moving towards the Aleppo front, and teams of Russian special forces are thought to be operating alongside both Syrian government and allied Hezbollah units.
So, for now, all eyes are on Aleppo.
But if Russia has shifted gears in its approach, so too have the Americans.
President Barack Obama's decision to double down on IS - not least by deploying up to 250 additional special operators in Syria to train and assist a coalition of Kurdish and Arab fighters - indicates that key outside players are already gearing up for an upsurge in the fighting.
Syria's multiple wars show no sign of ending.