Cuban President Fidel Castro has strongly criticised the use of biofuels by the US, in his first article since undergoing surgery last year.
Officials expect Mr Castro to return to public life soon
He said George W Bush's support for the use of food crops in fuel production would cause 3bn deaths from hunger.
The article in the Granma newspaper did not mention Mr Castro's health.
Officials say they expect Mr Castro - who temporarily handed over power to his brother last July - to resume activities in government soon.
Last month, Mr Castro appeared in a live radio broadcast for the first time since falling ill.
The Cuban leader's failure to appear in public - and the silence from the Cuban authorities - had fuelled speculation about the seriousness of his condition.
Mr Castro's article appears in Thursday's edition of Granma, under the headline: "Condemned to premature death by hunger and thirst more than 3bn people of the world."
In it, he says he has been "meditating quite a bit since President Bush's meeting with North American automobile makers".
During that meeting on Monday, Mr Castro writes, "the sinister idea of converting food into combustibles was definitively established as the economic line of foreign policy of the United States".
Mr Bush has set targets for an increased use of ethanol - which in the US is mainly made from corn. The US government hopes this will reduce the country's dependence on foreign oil.
The US and Brazil recently signed an agreement to develop biofuels, and their presidents are expected to hold further talks on the matter at the weekend.