Ukraine participates in the investigation, despite the fact that Kiev violated international rules and did not close the airspace over the territory where the fighting took place.
The SBU or Ukranian military intelligence can commit an act of chemical terrorism in Donbas, in order to blame the separatists for this and escalate the conflict.
Recurring pro-Kremlin disinformation on Ukrainian aggression against Russia. euvsdisinfo.eu/disinformation-cases/?text=provocation&disinfo_issue=&date=,
More on the fighting in Eastern Ukraine: https://www.rferl.