Defying US pressure for democratic reforms, President Fidel Castro has led hundreds of thousands of Cubans onto the streets to back a constitutional amendment setting in stone his country's socialist system.

Surrounded by security men and other top communist leaders Mr Castro led the way along the Havana seafront and past the US diplomatic mission.

Come on, comrades! Everyone will participate in the great march against the lies of Mr W

Cuban protester

The BBC's correspondent in Havana, Daniel Schweimler, says the protest is the latest incident in an increasingly bitter attack against Washington's policy towards Cuba.

The move comes a month after dissidents on the island presented a petition, known as the Varela Project, to the National Assembly calling for greater civil liberties.

On a visit to Havana in May the former US president, Jimmy Carter highlighted the petition, which most Cubans had never heard of, and added his voice to the call for greater freedom.

No policy change

US President George Bush, speaking to Cuban Americans in Miami shortly afterwards, then reiterated his demand for greater democracy before Washington would consider easing its 40-year trade embargo and travel ban to the island.

Our correspondent says the huge rally is Mr Castro's response to that pressure, basically saying that there will be no change because the Cuban people do not want change.

Castro hopes to show that Cubans do not want change

He led a million or so flag-waving marchers along the Havana seafront, whilst schools and work places were closed for the day to enable more to gather in provincial capitals and towns across the country.

He called the rally earlier in the week to back a constitutional amendment that would declare Cuba's socialist system to be "untouchable", a state of workers, organised with all, and for the good of all.

Wearing his traditional olive green uniform and cap Mr Castro waved a small Cuban flag himself as the massive crowd marched towards the US mission.

"Come on, comrades! Everyone will participate in the great march against the lies of Mr W!" one man shouted into a megaphone, a reference to the US president.

Dissidents dismissed

Observers say the mobilisation was also in response to the proposed referendum, known as the Varela Project.

Schools and work places were closed to ensure a big turnout

Organisers submitted more than 11,000 signatures to Cuba's National Assembly on 10 May, demanding a referendum on civil liberties.

Our correspondent says the tone of Mr Castro's attacks against Washington has increased in bitterness - with him comparing some aspects of the US policy towards Cuba to those in Nazi Germany.

And that although some of his fellow Cubans join his protests with enthusiasm, others are pressured by the authorities into attending to present a united front against increasing demands for change.