Holding candles, people march on one of the city's main avenues to protest against the National Court's decision. AP / PA Images AP / PA Images / PA Images

Updated at 11pm

TENS OF THOUSANDS of people took to the streets of Barcelona tonight after a court ordered the detention of two Catalan separatist leaders, further inflaming tensions over Catalonia’s chaotic referendum on splitting from Spain.

Shouting “freedom” or “independence” and carrying candles, the demonstrators stood massed on a large boulevard in the city centre at nightfall before observing a long moment of silence.

Emilio Morenatti via PA Images Emilio Morenatti via PA Images

Around 200,000 people took part, a spokesman for Barcelona’s municipal police said.

Candle-lit demonstrations were also held in Girona, Reus and other Catalan cities in protest at the Madrid-based National Court’s ruling yesterday to keep Jordi Cuixart and Jordi Sanchez behind bars pending investigations into sedition charges.

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“They want us to be afraid so we stop thinking of independence, but the opposite will happen, we are more everyday and I think we will achieve it in the end,” Elias Houariz, a 22-year-old baker, told AFP at the rally.

The demonstration came as the clock ticks down to Thursday, the deadline Madrid has set for Catalonia’s separatist leader Carles Puigdemont to spell out whether or not he intends to declare independence outright following the banned 1 October referendum.

Puigdemont has so far declined to give a definitive response, calling instead for Spain’s Prime Minister Mariano Rajoy to come to the negotiating table.

Spain's top court also ruled Tuesday that a recent independence referendum in Catalonia was unconstitutional. AP / PA Images AP / PA Images / PA Images

But Rajoy rejects mediation as a non-starter and unless Puigdemont backs down, appears likely to start imposing direct control over the semi-autonomous region.

Doing so could further escalate Spain’s worst political crisis since it emerged from military dictatorship in 1977.

- Earlier -

A Spanish court ordered two powerful Catalan separatists to be detained, threatening a further escalation of the political crisis as both sides refuse to budge in their high-stakes standoff over the region’s independence bid.

People gather to protest against the National Court's decision to imprison civil society leaders without bail. AP / PA Images AP / PA Images / PA Images

Protests broke out in Catalonia’s capital Barcelona yesterday as news spread that Jordi Cuixart and Jordi Sanchez were being kept behind bars on sedition charges.

The pair are the leaders of pro-independence citizens’ groups Omnium Cultural and the Catalan National Assembly (ANC) respectively, both of which count tens of thousands of members and have emerged as key players in the Catalonia crisis.

They are accused of stirring up major protests in the run-up to the banned 1 October independence referendum in the region of 7.5 million people which has its own language and culture.

“The state is playing at provocation,” Catalan government spokesman Jordi Turull said after the National Court ruling, as the two groups furiously called on the people of Catalonia to protest, with a strike planned for Tuesday.

“I’m calling for Catalan society to peacefully protest tomorrow,” said Jordi Bosch, secretary general of Omnium Cultural.

A woman holds an estelada or independence flag on a motorcycle shortly after taking part in tonight's protest. Emilio Morenatti via PA Images Emilio Morenatti via PA Images

Calls for protest spread on social media with demonstrations planned in Catalonia and beyond, including London. Some people stopped work briefly at midday to call for the “release of political prisoners”.

Hundreds of independence supporters gathered outside Catalan government offices, some singing the region’s hymn and holding signs that read “Freedom for political prisoners”.

Freedom

Prior to his detention, Jordi Cuixart recorded a video message to be released only if he was held, which was sent out overnight.

“If you’re watching this video, it’s because the state has decided to deny me my freedom,” he said, adding that his organisation would work “underground” and peacefully to further their cause.

Catalan police chief Josep Lluis Trapero also appeared in court on sedition charges, facing up to 15 years in jail for allegedly encouraging protests and failing to stop the referendum — though he was allowed to walk free.

The ruling against Cuixart and Sanchez came after another day of twists and turns as Spain struggles with its worst crisis since it returned to democracy in 1977 following the death of dictator Francisco Franco.

Madrid warned Catalonia’s separatist leader Carles Puigdemont he only had three days to “return to legality” after he refused to say whether he would declare independence outright following the referendum outlawed by the courts and Madrid.

He had been initially ordered to give his answer by yesterday, but stopped short of giving a definitive response and instead called for talks with Prime Minister Mariano Rajoy.

Spain has given him until 8am on Thursday to clarify, but anything less than a full climb-down is likely to prompt moves by Madrid to impose unprecedented direct control over the semi-autonomous region.

“You still have time to answer clearly and simply,” Rajoy urged Puigdemont, warning that weeks of instability were damaging the Spanish economy.

As if to emphasise the point, Madrid announced late Monday that it was cutting its growth forecast for next year from 2.6% to 2.3%, blaming uncertainty created by the Catalan crisis.

- © AFP 2017

Read: Spain gives Catalonia deadline of 9am Thursday to make up mind on independence >