Venezuelan president Hugo Chavez will face a "complex and hard" post-surgery process after undergoing his fourth cancer-related operation in Cuba, according to his vice president.
Nicolas Maduro made the announcement in Caracas, a day after Mr Chavez underwent the procedure.
Mr Maduro called for Venezuelans to calmly face what he says will be "hard, complex and difficult days" ahead.
"It was a complex, difficult, delicate operation," said Mr Maduro, adding that indicates "the post-operative process is also going to be a complex and hard process".
The vice president, whom Mr Chavez named over the weekend as his chosen political heir, was flanked by National Assembly President Diosdado Cabello and Oil Minister Rafael Ramirez, who had accompanied the president in Havana during the surgery.
Mr Maduro said Mr Cabello and Mr Ramirez had returned to Caracas at 3am and they had talked about the situation until daybreak.
Mr Maduro had a solemn expression as he spoke, and his voice was hoarse and cracked at times.
He called for unity in the country as it faces "complex and difficult scenarios".