Russia will not stay on the sidelines if Ukraine starts carrying out a genocide against its own, Ukrainian, population in Donbas.
Recurring pro-Kremlin disinformation on Ukrainian aggression. euvsdisinfo.eu/disinformation-cases/?text=&disinfo_issue=&disinfo_keywords%5B%5D=77110&date=
No evidence given for a threat of genocide in Ukraine. The word genocide is frequently used in pro-Kremlin disinformation https://euvsdisinfo.eu/disinformation-cases/?text=genocide&disinfo_issue=&disinfo_language%5B%5D=rus&date= but it seldom corresponds to the actual definition of a genocide http://www.un.org/en/genocideprevention/genocide.html
More on the fighting in Eastern Ukraine: www.rferl.org/a/29241384.html
The Office of the Prosecutor of the International Criminal Court has stated that “the information available suggests that the situation within the territory of Crimea and Sevastopol amounts to an international armed conflict between Ukraine and the Russian Federation. This international armed conflict began at the latest on 26 February when the Russian Federation deployed members of its armed forces to gain control over parts of the Ukrainian territory without the consent of the Ukrainian Government https://www.icc-cpi.int/iccdocs/otp/161114-otp-rep-PE_ENG.pdf
For further debunking see https://euvsdisinfo.eu/report/the-osce-the-pentagon-nato-headquarters-and-the-council-of-europe-do-not-recognize-the-facts-of-russias-aggression-against-ukraine-primarily-the-intrusion-of-russian-tanks-and-paratroopers-into-do/