Cuban leader Fidel Castro says he is in a stable condition and good spirits following surgery, according to a statement read on Cuban TV.
Fidel Castro (left) is temporarily handing over to his brother (right)
"I feel perfectly fine," Mr Castro was quoted as saying.
On Monday he handed power temporarily to his brother Raul, to recover from his treatment for internal bleeding.
Earlier the Cuban leader, who turns 80 this month, was quoted as saying that a punishing schedule in recent weeks had affected his health.
It is not clear whether he is in hospital or recovering at home.
The statement expressed gratitude for the good wishes Mr Castro had received from around the world, and urged Cubans to maintain their daily routines.
"Everyone needs to struggle, and work," he is quoted as saying.
This is the first time Mr Castro has relinquished any of his duties as head of the communist state since he came to power in 1959.
The BBC's Stephen Gibbs in Havana says most Cubans are taking the news of their leader's sickness in their stride.
The White House has said it is monitoring events while Cuban exiles have been celebrating in Miami.
Raul Castro, the 75-year-old defence minister, has long been designated as his brother's successor should he become incapacitated.
'Normal for now'
Fidel Castro has been among the world's longest-ruling leaders, outlasting nine US presidents.
Shops and offices are open in Havana and there is no sign of extra security, our correspondent says.
Ricardo Alarcon, Cuba's parliamentary speaker, sought to play down the gravity of the leader's condition.
The "final moment is still very far away", he hold the government's Prensa Latina news service.
Celebrations taking place among Miami's Cuban exiles were, he added, "sickening" and he appealed for Cubans to unite around Fidel Castro.
Our correspondent in Havana reports that there is much genuine sadness that the veteran president has been taken ill.
However, he adds, some are more discreetly voicing hope that change may be in the air.
"Everything's normal here - for the moment," hospital worker Emilio Garcia, 41, told US news agency the Associated Press in the capital.
"But we've never experienced this before - it's like a small test of how things could be without Fidel."
Governments in Latin America have wished Mr Castro well while the US state department said it was monitoring events and that it reaffirmed its support for a democratic transition in Cuba.