A state-controlled newspaper in Cuba has published the first photographs of President Fidel Castro since he had intestinal surgery two weeks ago.
The paper also carried an 80th birthday message attributed to Mr Castro, saying he was recovering but warning Cubans to be ready for "adverse news".
He has not been seen since he handed power temporarily to his brother.
Raul Castro has made his first public appearance since taking over, welcoming Venezuela's president to Havana.
Official birthday celebrations were cancelled but the Cuban capital held a giant concert on Saturday.
The pictures released by the Juventud Rebelde newspaper show Mr Castro speaking on the phone and holding Saturday's edition of the Communist Party newspaper Granma, in an apparent move to show the pictures are current.
In his statement, Mr Castro said his health had improved considerably but cautioned that his recovery would not be quick.
"I ask you all to be optimistic and at the same time to be ready to face any adverse news," the statement said.
Havana's party to honour Fidel Castro lasted all night
He thanked Cubans for their loving support and said that on the day of his birthday, 13 August, he "felt very happy".
The photographs in Juventud Rebelde came a day after Granma carried the most detailed account to date of Mr Castro's health since he underwent surgery on 31 July.
In a report of a visit to the Cuban president's bedside, the paper suggested Mr Castro was "firm like a caguairan" - likening Cuba's revolutionary leader to a sturdy tropical hardwood tree.
Recounting the observations of an unidentified visitor, Mr Castro was said to be "up and about, like someone anticipating new victories".
Neither Mr Castro nor his brother, Raul, have been seen in public for the past fortnight, fuelling speculation both in Cuba and in Florida, home to many Cuban exiles, about who is in charge.
The BBC's Stephen Gibbs in Havana says Sunday's pictures are clearly aimed at conveying a message of continuity to the Cuban people.
Immediately after surgery, Mr Castro asked for his birthday celebrations to be postponed.
But hundreds attended a huge concert on Saturday, held outside the US Interests Section in Havana and lasting all night.
President Hugo Chavez of Venezuela, a staunch ally, arrived in Cuba on Sunday where he was saluted and hugged by Raul Castro at the airport.
State TV showed the encounter but neither man commented for the cameras.
Mr Chavez had said earlier he would bring as gifts a dagger and a cup once carried by the 19th Century Latin American independence fighter Simon Bolivar:
"I'm taking him a good present, a good cake, and there we will celebrate the 80 years of that great figure of our America."
Fidel Castro became Cuban president 47 years ago after leading the overthrow of Fulgencio Batista.
He is one of the world's longest-ruling leaders, and has outlasted nine US presidents.