The European Council President condemned Russia's peacekeeping forces, present in Nagorno-Karabakh since a peace deal was brokered by Moscow in 2020, for standing aside as Baku launched its military action.
"It is clear for everyone to see that Russia has betrayed the Armenian people," Michel told Euronews' Global Conversation.
"Russia wanted to have soldiers on the ground to guarantee this peace and security agreement. But we see that the military operation was launched without the slightest reaction from the Russian peacekeeping forces in the territory. The European Union, on the other hand, had no force or military presence on the ground," he added.
Baku recently regained control of Nagorno-Karabakh from Armenian separatists after launching a military offensive.
An estimated 100,000 ethnic Armenians have since fled in fear of persecution as Azerbaijani forces tighten their grip on the region.
Experts say Baku's actions amount to a war crime, and Armenia has accused its neighbour of pursuing ethnic cleansing.
Michel has played a leading role in recent EU attempts to de-escalate the decades-old conflict, convening both sides for talks in Brussels as Pashinyan looked to the West for support.