HAVANA (Reuters) - Former Cuban leader Fidel Castro, who has lived in seclusion since falling ill four years ago, will appear on Cuban television and radio on Monday evening to discuss his theory that the world is on the verge of nuclear war, the Communist Party newspaper Granma said in its Monday online edition.

Former Cuban leader Fidel Castro sits at the National Centre for Scientific Investigation (CNIC) in Havana July 7, 2010. REUTERS/Alex Castro

The appearance will mark the second time in less than a week that the suddenly resurgent 83-year-old has made a public appearance, after staying out of view, except in occasional photographs and videos, since undergoing emergency intestinal surgery in July 2006.

Last Wednesday, he made a visit to a Havana scientific center that was disclosed in a blog on Saturday.

Castro writes opinion columns, or “Reflections,” for Cuba’s state-run media that in recent weeks have focused on his prediction that nuclear war will soon break out, sparked by a conflict between the United States and Iran over international sanctions against Iran’s nuclear activities.

“The empire is at the point of committing a terrible error that nobody can stop. It advances inexorably toward a sinister fate,” he wrote on July 5.

The “empire” is how Castro usually refers to the United States, his bitter foe from the time he took power in Cuba in a 1959 revolution.

In a column published on Sunday night, Castro said the “principal purpose” of his writings has been to “warn international public opinion of what was occurring.”

He said he has reached his dire conclusion based in part on “observing what happened, as the political leader that I was during many years, confronting the empire, its blockades and its unspeakable crimes.”

The columns have attracted little attention internationally and caused little reaction in Cuba, but Castro promised to continue his lonely fight to warn the world of the coming disaster.

“I don’t hesitate in running risks of compromising my modest moral authority,” he wrote on Sunday. “I will continue writing ‘Reflections’ about the topic.”

Castro ruled Cuba for 49 years before provisionally ceding power to younger brother Raul Castro following his 2006 surgery.

Citing age and infirmity, he officially resigned in February 2008 and Raul Castro, now 79, was elected president by the National Assembly.

Fidel Castro’s reappearance comes as Cuba is preparing to release 52 political prisoners, all jailed in a crackdown on the opposition in 2003 while he was still in power.