HAVANA (AFP) - Fidel Castro blasted US President Barack Obama Friday in provocative May Day remarks, saying the United States only wanted Cuba to return to the fold, like slaves. Castro, 82, who led Cuba for almost 50 years and remains head of the Cuban Communist Party, was not in outreach mode, though Obama and Cuban President Raul Castro, 77, have willingness to ease Cold War-era tensions. Today, they stand ready to forgive us - as if we would resign ourselves to returning to the fold like slaves, who after tasting freedom, go back to the yoke and whip, Fidel Castro said in a defiant address published in Cuban state media to mark May Day. Castro, who for decades referred to the United States as the enemy, warned: The (US) adversary must never delude itself into thinking that Cuba will surrender. President Raul Castro, decked out in a tropi-casual guayabera shirt and farmers hat, meanwhile led over an estimated 500,000 Cubans called out to march in the annual May Day parade. Marchers, waving signs with slogans like Down With the Genocidal Blockade, were calling for an end to the US economic embargo on Cuba. President Raul Castro bluntly declared on Wednesday that Cuba will not make symbolic gestures to appease the United States, even while leaving a door open to more dialogue. In a first direct Cuban response to a US call for gestures from communist Cuba, Castro told a Non-Aligned Movement meeting in Havana that any forthcoming shows of goodwill must start from the US side. Cuba is not the one that stops its countrys businessmen from doing business with ours; Cuba is not the one punishing financial transactions by US banks, the Cuban leader said. Cuba does not have a military base on US territory against the will of its people, Raul Castro stressed in a clear reference to the Guantanamo prison, which has been steeped in controversy worldwide.