Havana, Cuba (AFP) — A Cuban activist jailed for putting up anti-government posters and defacing a Fidel Castro billboard suffered cardiac arrest after 48 days on hunger strike, NGOs said Thursday.

Roilan Alvarez Rensoler, 40, began the strike after being detained on January 31 in the eastern province of Holguin and faces charges of “propaganda against the constitutional order.”

“His situation is quite delicate,” his sister, Arianna Alvarez Rensoler, told AFP.

The activist was resuscitated after suffering cardiac arrest in recent hours, Miami-based rights group Cubalex said in a post on X, warning of an “imminent risk” to his life.

Alvarez Rensoler was hospitalised on March 4 due to his deteriorating health as a result of the hunger strike, said Justicia11J, a group tracking arrests stemming from massive anti-government protests in July 2021.

His sister has not been granted access to her brother at the hospital.

Justicia11J called for his immediate release, warning that his “life is in danger after 48 days of sustained hunger strike.”

Alvarez Rensoler is a member of the opposition movements Patriotic Union of Cuba (UNPACU) and Cuba Decide.

He previously served a one-year prison sentence for “contempt.”

Hunger strikes are a recurring form of protest among jailed Cuban dissidents.

The Inter-American Commission on Human Rights called Wednesday for the immedial release of Alvarez Rensoler “and of every person detained for political reasons.”

Cuba’s communist authorities said last week that they would release 51 prisoners after talks with the Vatican, which has in the past acted as mediator between Havana and Washington.

Fourteen people who participated in the protests of July 11, 2021, have been released, according to Cubalex and Justicia11J.

There were at least 760 political prisoners in Cuba as of March 13, including 358 who participated in the July 2021 protests, according to Justicia11J.

Cuba denies holding political prisoners and accuses dissidents of being “mercenaries” of the United States.