Israel's YNet reports Aug. 31 that Russian fighter pilots are expected to begin arriving in Syria in the coming days, to begin sorties against ISIS and rebel forces. The report cites diplomatic sources to the effect that "a Russian expeditionary force has already arrived in Syria and set up camp in an Assad-controlled airbase. The base is said to be in area surrounding Damascus, and will serve, for all intents and purposes, as a Russian forward operating base. In the coming weeks thousands of Russian military personnel are set to touch down in Syria, including advisors, instructors, logistics personnel, technical personnel, members of the aerial protection division, and the pilots who will operate the aircraft."
The report also notes Russia's growing if informal alliance with Iran. The infamous Iranian Quds Force commander Maj. Gen. Qasem Soleimani apparently just visited Moscow where he and Russian officials arrived at a consensus: "Make any effort necessary to preserve Assad's seat of power, so that Syria may act as a barrier, and prevent the spread of ISIS and Islamist backed militias into the former Soviet Islamic republics."
So it appears that Russia will be joining with the US-backed coalition in bombing ISIS—but also bombing the Syrian rebels that are being backed by the US (however half-heartedly). And while Iran is part of the Great Power convergence against ISIS, in a de facto alliance with the US in Iraq, Tehran and Washington are backing rival forces in Syria. (Although Iran and Russia are backing the Assad dictatorship far more aggressively than the US is backing the rebels. Oryx Blog cites claims from Syrian rebels that Russian elite forces are already fighting against rebels in the Alawite heartland of Latakia.)
Russia of course has been militarily backing Assad throughout the war, and recently signed a deal to exploit oil on the Syrian coast—not far from where Russia maintains a naval base on Syrian territory at Tartus.
Meanwhile BBC News reports that Turkey has carried out its first air-strikes against ISIS in Syria as part of the US-led coalition. The report states that Turkey bombed ISIS targets in Syria on July 24, but not officially as part of the coalition. We noted then that media reports actually suggested Turkey was hitting anti-ISIS Kurdish forces (and by tank fire from across the border, not air-strikes). Since then, Turkey has been carrying out air-strikes against PKK targets in Iraq while also launching an offensive against the Kurds within its own territory. But Turkey has perhaps been restrained by internal Kurdish and leftist resistance (and quiet White House pressure?) from actually invading Syria to establish a "buffer zone." It will be interesting to watch whether Turkey will now indeed bomb ISIS targets in Syria, or anti-ISIS Kurdish targets. (Or a lot of Kurdish targets and a few ISIS targets for appearances' sake.)
Turkey has up to this time been effectively collaborating with ISIS, using them in a pincer action against the Syrian Kurds. It initially seemed that a free hand to crush the Syrian Kurds could be that pay-off for Turkey agreeing to join the US-led coalition against ISIS and open Incirlik Air Base to US forces.
And while Turkey and Russia will both (supposedly) be bombing ISIS targets in Syria, they are bitter regional rivals—last year, their respective warplanes played chicken over the Black Sea, in a very dangerous display of brinkmanship.
Complicated enough? That's why they call it a Great Game.