Mr Arcos fought alongside the island's leader, Fidel Castro, in the attack that launched the 1959 revolution.

But he came to believe the government was too authoritarian, and was jailed for counter-revolutionary activities.

He later founded the Cuban Committee for Human Rights, one of the first big dissident groups to emerge in Cuba.

"He was one of the most respected people in the human rights movement in Cuba," fellow activist Carlos Menendez told the Associated Press.

Bullet wound

Mr Arcos was shot in the hip during the failed assault on the Moncada barracks led by Fidel Castro in 1953, and was left partially paralysed.

The rebel group was imprisoned but later pardoned, and Mr Arcos later toured Latin America gathering supplies of money and weapons for another attempt to overthrow the dictator Fulgencio Batista.

Following their triumph in 1959, Mr Arcos became Cuba's ambassador to Belgium, but became disillusioned with the revolution, reportedly regretting that it had taken a turn towards communism from nationalist beginnings.

He was successively imprisoned, on one occasion for illegally attempting to leave the country.