Fidel Castro waves Saturday during a special session of parliament, his first official government appearance in front of lawmakers in four years. (Javier Galeano/Associated Press)

Fidel Castro appealed to U.S. President Barack Obama to stave off global nuclear war in an emphatic address to parliament Saturday in Havana that marked his first official government appearance since emergency surgery four years ago.

Castro, who turns 84 in a week, wore olive-green fatigues devoid of any military insignia and arrived on the arm of a subordinate who steadied him as he walked.

The approximately 600 lawmakers present sprang to their feet and applauded, as the grey-bearded revolutionary stepped to a podium that had been set up for him, grinning broadly and waving.

"Fidel, Fidel, Fidel!" chanted the members of parliament. "Long live Fidel!"

Castro has been warning in written opinion columns for months that the U.S. and Israel will launch a nuclear attack on Iran and that Washington could also target North Korea — predicting Armageddon-like devastation and fighting he expected to have already begun by now.

"Eight weeks ago, I thought that the imminent danger of war didn't have a possible solution. So dramatic was the problem that I didn't see another way out," Castro told the legislature. "I am sure that it won't be like that and, instead ... one man will make the decision alone, the president of the United States."

He added of Obama, "Surely with his multiple worries, he hasn't realized this yet, but his advisers have."

Castro didn't mention domestic Cuban politics or the foundering economy — instead sticking to the threat of war, the issue for which he convened Saturday's special session of parliament.

Castro's speech lasted barely 11 minutes — possibly a record for the man who became famous for his hours-long discourses during 49 years in power — and was largely devoid of his usual U.S. bashing.

He referred to the United States as "the empire" only a few times — though he did say that if Obama didn't intervene he would "be ordering the instantaneous death ... of hundreds of millions of people, among them an incalculable number of inhabitants of his own homeland."

In Washington, there was no immediate response from the White House.

Castro moved to a seat after his speech, and was briefly approached by his wife, Delia Soto del Valle. The couple rarely appeared in public together in the past, but Soto has been seen with Castro more frequently of late.

It was Castro's first appearance in parliament or at a government act since shortly before a health crisis in July 2006 that forced him to cede power to his younger brother Raul — first temporarily, then permanently.

He underwent emergency intestinal surgery prompted by an illness whose exact nature has been kept a state secret, and spent years recovering in an undisclosed location.