Miguel Díaz-Canel told crowds in Havana the US is trying to break down Cuba’s political system.
He declared America aims for total control across the island.
Díaz-Canel branded US policies a case of political genocide during July 26 events.
He warned this is a danger to the country's right to govern.
Raúl Castro stayed away from the biggest rally.
Tensions stay high because of sanctions and US political pressure.