HAVANA – A lively and healthy-looking Fidel Castro appealed to President Obama to stave off global nuclear war in an emphatic address to parliament Saturday 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 gray-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.

Still, his attendance, along with a slew of recent public appearances following a nearly four-year absence from public view, is sure to raise more questions about how much of a leadership role Castro is ready to resume.

Is he itching to retake his position as Cuba’s “maximum leader” — or simply well enough to warn lawmakers in person that the end of the world could be near?

Castro’s speech lasted barely 11 minutes — possibly a record for the man who became famous for his hourslong discourses during 49 years in power — and was largely devoid of his usual America bashing. He referred to the U.S. 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.”

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 him more often 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.

Lawmakers have always left an empty chair to the right of Raul. It was in its usual spot Saturday — but Fidel did not sit in it.

Instead, he sat next to Parliament head Ricardo Alarcon. The two consulted and cracked jokes during the assembly’s one-hour-and-40-minute session. Raul Castro sat nearby, though on another part of the stage, listening intensely to the proceedings and taking notes when Fidel delivered his speech.

While it was the first time the brothers have appeared together publicly since Fidel fell ill, neither made any effort to approach the other or to make eye contact.