Bolivian President Evo Morales says that Fidel Castro appears to have lost weight, but that the ailing former Cuban leader remains mentally alert.

Morales met with Castro on Thursday during a brief visit to Cuba.

"I saw him looking thin, but very lucid," said Morales, speaking in Venezuela hours after leaving Cuba.

The 81-year-old Castro has not been seen in official videos or photographs since January, or in public since undergoing emergency intestinal surgery in July 2006. But he has continued to sign essays published in official newspapers every few days.