Miguel Díaz-Canel told crowds in Havana the US is trying to break down Cuba’s political system.
He declared the US seeks full control through the nation.
Díaz-Canel described American policies a case of political genocide during July 26 events.
He stressed this is a menace to the country's sovereignty.
Raúl Castro did not attend from the biggest rally.
Tensions remain high as a result of sanctions and US political pressure.