The SU-22 (NATO code name Fitter) was shot down by a US F/A 18 (Super Hornet) (Su-22, Russian designation, 'Strizh, meaning 'martlet' - a bird ike a swallow)after it unloaded ordnance onto a position held by US-friendly rebels. Predictably, the Russians issued a warning, as was previously the case when US air assets interdicted a bunch of Iranian proxies who were advancing toward a coalition base at Tanf. Syrian pilots have no business dueling with US aircraft, particularly in an old airframe like the 22 (first flight 1966). However, the Russians might give US air a run for its money, up to a point. The point is that US rules of engagement are clear and the Russians know what they are, so this is just political posing. Some HFers have flown combat air. Would be interesting to hear some opinions. NATO assigns codewords, starting with 'F' to Soviet, oops, belay that - RUSSIAN fighters. It's just a convenient shorthand. Fitter, Flanker, Fencer, Fulcrum, Foxbat are a few (recall that Clint Eastwood flew one up to the Arctic)
https://news.usni.org/2017/06/18/navy-super-hornet-shoots-syrian-fighter-near-raqqah https://theaviationist.com/2017/06/19/u-s-navy-fa-18e-super-hornet-downs-syrian-su-22-near-raqqa-syria-and-here-is-everything-we-know/ yesterday You'd think Assad would have the common decency not to send married men with children up to take on Super Hornets in the equivalent of a 1968 Ford pickup
They're allied with Syria so they were obligated to say something. That said, I would still take this very seriously because any engagement with them has the potential to spiral out of control, and we all know what that can lead to.