Fidel Castro, the former Cuban president, has attacked Barack Obama, the US president, accusing him of supporting "Israeli genocide" against the Palestinians.
Castro, who had recently praised Obama as "honest" and "noble", said in a column posted on a government website that Obama was continuing the policies of George Bush, his predecessor, by supporting Israel.
The former Cuban leader, who was succeeded by his brother Raul as president in February, accused the US of having enabled Israel to become an "important nuclear power".
He also accused the US of giving Israel military aid with which it "threatens extreme violence against the population of all the Muslim countries".
Castro highlighted statements made by the Obama administration that reiterated its strong support for Israel, which recently carried out a 22-day assault on Gaza in which more than 1,300 Palestinians were killed.
Obama has repeatedly reiterated his strong support for Israel's right to defend itself against rocket attacks by Palestinian fighters.
Fidel Castro also criticised Obama for suggesting Cuba would have to make concessions before it considers returning the territory of the US naval base at Guantanamo Bay.
"Maintaining a military base in Cuba against the will of the people violates the most elemental principles of international law," Castro said.
"Not respecting Cuba's will is an arrogant act and an abuse of immense power against a little country," he added.
Cuba indefinitely leased Guantanamo to the US in 1903 after the US occupied the country during the 1898 Spanish-American War.
Castro has claimed that the base at the south-eastern tip of Cuba was taken over illegally.
Obama said during his election campaign he was willing to consider holding talks with nations with poor relations with the US, such as Cuba and Iran.