These have been there from before, there is a russian airbase in armenia, the mig-29s there are soviet era and old, and not equipped for BVR combat, and in poor condition, russia meant to replace them with some Su-30s. Don't bother with Austin Powers and his BS about them being the same as f-18s. Its unlikely Russia intervenes, as Putin has said that Russia is under no CSTO obligations to fight for armenia outside of armenian recognized territory, and Russia has a working relationship with Azerbaijan. Not to mention that Pashinyan's election made relations worse.