Fidel Castro threw his first punch at President Barack Obama after several weeks of praise for the new leader, demanding the US Return Guantanamo Bay military base to Cuba and criticizing the US Defense of Israel.
Castro's latest essay, published on an official Web site on Thursday, came one week after he called Obama "intelligent and noble" and said he would cut back on his writings to prevent interfering with Cuban government decisions.
The missive raised new questions about what role he maintains in policy-making, especially coming while his brother, President Raul Castro, was in Moscow on an official visit.
The ailing 82-year-old former president wrote that if the US Doesn't give the US Base at Guantanamo back to Cuba, it will be a violation of international law and an abuse of American power against a small country.
The US President must "respect this norm without any condition," Castro wrote.
Obama has ordered the prison for terror suspects on the US Base to be closed within a year, but Cuba also demands the return of the 45-square-mile territory the base occupies in the island's east.
Raul Castro and other government officials have called for the return of the base, but with less critical words and tone.
The US, which acquired Guantanamo more than 100 years ago, considers it strategically important to maintain.