Cuban leader Fidel Castro has written a second newspaper article within a week, again criticising US biofuels policy.
When in full health, Mr Castro regularly writes length articles
Writing in the Granma newspaper, Mr Castro said a US drive to back crop use for fuels would raise prices and cause more hunger in developing countries.
Mr Castro handed power to his brother Raul in July after undergoing surgery, and has not appeared in public since.
Correspondents say his articles in the Communist Party's official paper may be a sign of a return to active politics.
The Cuban president's failure to appear in public - and the silence from the Cuban authorities - had fuelled regular speculation about the seriousness of his condition.
Officials have said they expect Mr Castro to resume activities in government soon.
Earlier in the year, Mr Castro appeared in a live radio broadcast for the first time since falling ill.
But the health of the 80-year-old leader was not mentioned in either of his Granma articles.
In Wednesday's column, Reflections of The Commander-in-Chief, Mr Castro criticised President Bush's plan to increase the use of foodstuffs like corn for fuel to run cars.
He said Mr Bush had "declared his intention to apply this formula on a world scale, which means none other than the internationalisation of genocide".
Mr Bush has set targets for an increased use of ethanol - which in the US is mainly made from corn.
The US government, which recently signed a biofuel agreement with Brazil, hopes this will reduce the country's dependence on foreign oil.
But Mr Castro wrote that dozens of nations do not have oil and cannot produce corn or other grains to make ethanol because they lack water.
The surge in demand for corn would push up grain prices while the threat of a US invasion of Iran keeps oil prices high, he wrote.
He asked: "Where are the poor countries of the Third World going to get the minimum resources to survive?"
Mr Castro also wrote of the current situation in Iran, where 15 British navy personnel are being held accused of entering Iranian territorial waters.
He described the incident as a provocation by Britain.