Spain's top court has officially ruled that Catalonia's disputed independence referendum was illegal because a regional law that backed it was against the country's constitution.

Key points: Spain's Constitutional Court said the referendum was unconstitutional

Spain's Constitutional Court said the referendum was unconstitutional Catalan leaders have been given until Thursday to renounce independence

Catalan leaders have been given until Thursday to renounce independence A spokesman said leaders will not be "giving in" to Spain

The Catalan regional parliament passed the so-called "self-determination referendum law" in early September, and regional leaders went on to stage the October 1 referendum on whether the region should separate from Spain.

They say the poll turned back an affirmative response and that the result gave the region a mandate to declare independence.

Spain's Constitutional Court had earlier suspended the law temporarily while judges assessed the Spanish Government's objection to it.

In its ruling on Tuesday, the court said the law was against national sovereignty and the "indissoluble unity of the Spanish nation" — the court said the parliamentary session that approved the law also violated the country's constitution.

Catalan leaders also refused on Tuesday to bow to the Spanish Government's demand that it renounce a symbolic declaration of independence, setting it on a political collision course with Madrid later this week.

The Spanish Government has threatened to put Catalonia, which accounts for a fifth of the economy, under direct central rule if its Government does not abandon independence by Thursday local time.

But Catalonia's Government rejected Prime Minister Mariano Rajoy's deadline.

"Giving in forms no part of this Government's scenarios," Catalan government spokesman Jordi Turull said.

"On Thursday, we won't give anything different than what we gave on Monday."

Sorry, this video has expired Spain gives Catalan leader 5 days to clarify independence

Spain accused of taking 'political prisoners'

Spain's biggest political crisis in decades worsened on Monday night when Madrid's High Court jailed the heads of Catalonia's two main separatist groups pending an investigation for alleged sedition.

The Catalan Government accused Madrid of taking "political prisoners."

Thousands of people protested in Barcelona on Tuesday to demand the release of the two Catalan pro-independence activists.

The demonstrators flooded a main avenue holding up candles and pro-independence "estelada" flags and chanted "political prisoners, freedom".

Thousands of people gathered in Barcelona to protest against the imprisonments. ( AP: Emilio Morenatti )



The jailed activists are Jordi Sanchez and Jordi Cuixart, who lead two different grassroots groups.

On Monday, a Madrid judge provisionally jailed Sanchez and Cuixart in a sedition investigation. The judge ruled they were behind huge demonstrations Sept. 20-21 in Barcelona that hindered the police operation against preparations for an Oct. 1 independence referendum.

Spain's top court has ruled that the referendum was unconstitutional, adding legal weight to the government's efforts to block an attempt by the region to break away from Spain.

Catalan leader Carles Puigdemont, in a tweet following the detentions, said: "Sadly, we have political prisoners again."

The phrase was an allusion to the military dictatorship under Francisco Franco, when Catalan culture and language were systematically suppressed.

It carries an emotional resonance given fascism is still a living memory for many Spaniards.

Justice Minister Rafael Catala hit back, saying the jailing of the leaders of the Catalan National Assembly and Omnium was a judicial, not a political, decision.

"We can talk of politicians in prison but not political prisoners," he said.

"These are not political prisoners because yesterday's prison ruling was due to a [suspected] crime."

The crisis has deepened divisions at the heart of Spain's young democracy, underlining the complex sense of nationhood in the euro zone's fourth largest economy.

In Madrid, unionists drape their homes in the national flag, while Barcelona apartment buildings are festooned with Catalan flags.

Street protests of hundreds of thousands of people have been held on both sides of the divide, including in Catalonia.

Sorry, this video has expired The day of the vote was met by violence

AP/Reuters