One was led by Ismael Frías and affiliated to the International Secretariat of the Fourth International (ISFI); the other led by Félix Zevallos and affiliated to the International Committee of the Fourth International (ICFI). It was this second group that Hugo Blanco joined in 1958, to organise activities under the co-ordination of Nahuel Moreno. In the role, he held a peasant uprising in La Convención in 1962, for which he was jailed and then exiled.