Fidel Castro sought to reassure Cubans after intestinal surgery forced him to temporarily cede power to his brother for the first time in 47 years, releasing a statement saying his health is stable, his spirits good and the defense of the island guaranteed.

Raul Castro, meanwhile, has remained silent and out of sight, issuing no statements of his own.

"The important thing is that in the country everything is going perfectly well, and will continue to do so," said the statement by the elder Castro, who temporarily handed power to his brother on Monday night after surgery.

Castro, 79, did acknowledge the operation was serious, saying "I cannot make up positive news." But he said his health was "stable" and "as for my spirits, I feel perfectly fine," according to the statement read on government television Tuesday night.

CountryWatch: Cuba

He apologized for not giving more details, but said the threat posed to his government by the U.S. means his health must be treated as "a state secret." No images of the leader were shown.

Castro expressed his gratitude for the good wishes he received from leaders and supporters around the world and called on Cubans to remain calm as they carried out their daily routines.

"The country is prepared for its defense," he said, apparently to assure Cubans the island was safe from potential U.S. attack.

Parliament speaker Ricardo Alarcon dismissed suspicions among exiles in Miami that Castro was dead, telling the government's Prensa Latina news service that the Cuban leader's "final moment is still very far away."

Still there were some signs of anxiety among Cubans.

"Everything's normal here — for the moment," said 41-year-old hospital worker Emilio Garcia. "But we've never experienced this before — it's like a small test of how things could be without Fidel."

The leaders of China, Venezuela, Brazil, Bolivia and Mexico were among many wishing Castro well. But in Washington, politicians were already speculating about a post-Castro Cuba, and in Miami, Cuban exiles celebrated in the streets — demonstrations Alarcon called "vomit-provoking acts" led by "mercenaries and terrorists."

In Cuba, dissidents kept a low profile while watching for signs of Castro's condition. It was unknown when or where the surgery took place or where Castro was recovering.

The main newscast on state-run television Tuesday ran a string of man-on-the-street interviews with Cubans wishing Castro well and professing confidence in the revolution's staying power. The anchor said Castro had the people's "unconditional support."

Cubans were stunned when Castro's secretary read a letter on state television Monday night announcing their leader was temporarily turning over power to his 75-year-old brother Raul, the island's defense minister and his designated successor.

In that first letter, Castro, who turns 80 on Aug. 13, said doctors operated to repair a "sharp intestinal crisis with sustained bleeding."

Alarcon said Castro made a point of delegating specific responsibilities to his brother and six other leading Cuban officials when his doctors told him to rest — a decision he said was made by a man "completely conscious and able to adopt these resolutions."

The calm delivery of the initial announcement appeared intended to signal that any transition of power would be orderly. Yet some feared resentment over class divisions could spark conflict if a political vacuum develops.

"It's better for things to move slowly, instead of abrupt change," Garcia said. "But people are a bit nervous — anything could happen."

Dissidents said they expected the government to be on the defensive, with a high security presence and a low tolerance for political acts.

"It's clear that this is the start of the transition," said activist Manuel Cuesta Morua. "This gives Cuba the opportunity to have a more rational leadership" because top leaders will be forced to work together rather than following one man.

In Washington, the State Department said it would support a democratic transition in Cuba. "We believe that the Cuban people aspire and thirst for democracy," spokesman Sean McCormack said.

But a Cuban fisherman said he had a message for the U.S. government: Stay out.

"In my house, I don't allow any outsider to order me around," Lazaro Alfonso Gonzalez, 58, said at a pro-Castro rally in Havana. "Cuba is my home, and none of us will allow anyone to come here and tell us what to do."

Several hundred government supporters who gathered in Havana's Central Park also voiced support for Raul Castro.

"He's a great leader, too," Francisco Urbay, 66, said of the defense minister. "What's happened is that he's always had a giant by his side. Anywhere else in the world, he wouldn't be No. 2."

Fidel Castro, who took control of Cuba in 1959, has resisted repeated U.S. attempts to oust him as well as demands for multiparty elections and an open economy.

Doctors in the United States said Castro's condition could be life-threatening but since the details of his symptoms were not released it was hard to say what caused the bleeding: severe ulcers, a colon condition called diverticulosis or even cancer as an outside possibility.

Castro seemed optimistic that with time he'll resume his public role, asking in his letter that celebrations scheduled for his 80th birthday be postponed until Dec. 2, the 50th anniversary of Cuba's Revolutionary Armed Forces.

Castro has been in power since his armed revolution drove out dictator Fulgencio Batista on Jan. 1, 1959. He has since become the world's longest-ruling head of government, imposing a firm rule that has ensured Cuba's place among the world's five remaining communist countries — China, Vietnam, Laos and North Korea.

While Cubans in Miami have longed for Castro's death for years, talk of his mortality was taboo on the island until June 23, 2001, when he fainted during a speech in the sun. Although Castro quickly recovered, many Cubans understood for the first time that their leader would eventually die.