By Fergal Parkinson BBC Miami correspondent

Chants of "Cuba Libre" could be heard across Miami as President George Bush delivered a powerful speech on US policy towards Cuba.

Bush arrived through streets lined with Cuban and American flags marking the centennial celebrations of the Republic of Cuba.

After 44 years this is the best day I have had in exile. Our President has told us something very important, I think we are finished with Castro

Vera Hernandez, Cuban exile

On Calle Ocho, in the heart of the city's Little Havana district, flags waved, car horns sounded and Salsa music filled the air as Cuban exiles celebrated Mr Bush's most decisive and emotional address to date over US policies toward Cuba.

In the Versailles cafe, an oasis of Cuban life, crowds gathered all afternoon. They watched Bush's speech on specially erected big screens and the mood was elated.

Standing ovations

Addressing his audience in English peppered with a little Spanish, the president's speech started on a hard-line note. His emotive description of Fidel Castro as a cruel despot brought about the first of 12 standing ovations.

"Half a century ago the hopes for democracy were hijacked by a brutal dictator that cares everything for his own power and nada (nothing) for the Cuban people," he said.

Bush is suspected of coming to help brother Jeb

In the Versailles cafe, cheers and applause made Mr Bush's announcement almost inaudible as he called for free and fair elections, the freedom of political prisoners and independent trade unions.

"I am so happy," said Vera Hernandez. "After 44 years this is the best day I have had in exile. Our President has told us something very important, I think we are finished with Castro".

New initiatives

Despite his harsh tone, Mr Bush's speech stopped short of announcing further measures against Mr Castro. His new initiatives, he said, were aimed at helping the Cuban people, especially those who oppose the government.

He promised the resumption of a direct mail service to the island and the first tentative steps toward more humanitarian assistance. He also announced a scholarship programme for the children of political prisoners.

All presidents just want to get the strong vote of the Cuban exiles, I expect nothing from them

Carlos Basilio, Cuban exile

The timing of Mr Bush's speech was applauded by Joe Garcia, the Executive Director of the Cuban American National Foundation, the largest organisation of its kind in the country.

"The anniversary of the Cuban nation is tremendously important. In Cuba the ballot has not meaning, only the bullet... Today is an exercise in democracy," he said.

Vital votes

Others were more sceptical about Mr Bush's timing, coming just a week after ex-president Jimmy Carter's call for a relaxation of sanctions.

There has been speculation that the president is keen to distance himself from Mr Carter's remarks, and keep the favour of Cuban Americans who hold represent a strong political force in the state.

"I think President Bush will do nothing for the Cubans," said Carlos Basilio, who has lived in Miami since leaving Cuba 18 years ago.

"Just as all presidents do nothing for the Cubans. They just want to get the strong vote of the Cuban exiles, I expect nothing from them," he added.

Mr Basilio is not alone in seeing the president's announcement today as a political move.

The state of Florida is crucial both for the Republican party and the Bush family, in particular his brother Jeb, the current governor here, who faces a tough re-election battle in November.