Led by Catalonia's separatist president Carles Puigdemont, hundreds of thousands of independence supporters protested in Barcelona on Saturday, shouting "freedom" and "independence" after Madrid announced drastic measures to stop the region from breaking away.

"It's time to declare independence," said Jordi Balta, a 28-year-old stationery shop employee, adding there was no longer any room for dialogue.

The protest in the centre of the Catalan capital had initially been called to push for the release of the leaders of two hugely influential grassroots independence organisations, accused of sedition and jailed pending further investigation.

But it took on an even angrier tone after Prime Minister Mariano Rajoy announced his government would move to dismiss the region's separatist government, take control of its ministries and call fresh elections in Catalonia.

Municipal police said 450,000 people rallied on Barcelona's large Paseo de Gracia boulevard, spilling over on to nearby streets, many holding Catalonia's yellow, red and blue Estelada separatist flag.

Protesters greeted Puigdemont's arrival at the rally with shouts of "President, President." The rest of his executive was also there.

"The Catalans are completely disconnected from Spanish institutions, and particularly anything to do with the Spanish state," said Ramon Millol, a 45-year-old mechanic.

Meritxell Agut, a 22-year-old bank worker, said she was "completely outraged and really sad."

"They can destroy the government, they can destroy everything they want but we'll keep on fighting."

Catalonia is roughly split down the middle on independence, but residents cherish the autonomy of the wealthy, northeastern region, which saw its powers taken away under the dictatorship of General Francisco Franco.

As such, Madrid's move could anger even those against independence.

Barcelona's Mayor Ada Colau, who opposes the independence drive, tweeted: "Rajoy has suspended the self-government of Catalonia for which so many people fought. A serious attack on the rights and freedoms of everyone."

As a police helicopter hovered above, protesters booed and gave it the finger.

"I wish they would just go," said Balta, looking up at the sky.

The Spanish government's proposed measures still have to be approved by the Senate.

But the upper house is majority-controlled by Rajoy's ruling Popular Party and he has secured the support of other major parties, meaning they will almost certainly go through.

Source: AFP