Violence erupts after hundreds of thousands take to the streets Barcelona to protest jailing of pro-independence politicians

‘This kind of violence is unprecedented in Catalonia ... these people are not separatists," says Catalonia's interior minister

Rioters fought running battles with police in Barcelona after more than half-a-million people took to the streets to demonstrate against the convictions of political figures behind Catalonia’s independence movement.

A general strike had already shut down the city when 520,000 people took to the streets – including some who had marched for days from five neighbouring cities.

As night fell, masked youths blocked a broad boulevard close to the city's police headquarters, setting fire to large bins and throwing a hail of stones, cans and bottles towards massed lines of security forces in full riot gear.

Defending the police building, officers responded with repeated volleys of foam bullets, smoke grenades and tear gas, while a water canon roamed the area to douse flames.

A branch of the Santander bank was also ransacked amid the chaos, while officials said there were clashes in at least four other towns and cities in Catalonia.

The protests began after the Spanish Supreme Court decided to jail nine separatist leaders for their role in a failed 2017 independence referendum earlier this week, on charges including sedition.

Unlike the peaceful protests that led up to the independence ballot – which was ruled illegal by Madrid – scores have been arrested in violent exchanges with national and regional police.

Protesters have set up and ignited barricades in the streets of the Barcelona.

More than 200 police officers treated for injuries since Monday.

Health authorities said 62 people were harmed across Friday evening alone, including 41 in Barcelona.

Around 107 police vehicles have been damaged while 800 bins are reported to have been burned as barricades over the same period.

Spanish authorities suspect a secretive new group called Tsunami Democratic is using encrypted messages to orchestrate some of the attacks.

The group appeared in September and in just over six weeks has gained nearly 340,000 followers on its main channel in Telegram, a messaging app.

A National Court judge ordered the closure of websites linked to the group on Friday.

More than 120 people have been arrested during the demonstrations.

It comes amid fears the independence movement has been pushed towards violence by fringe separatist groups who do not share the core movement’s views on non-violent protest.

Rights group Amnesty International called on "all authorities" to refrain from contributing to the escalation of tensions in the streets and to respond "proportionally" to outbreaks of violence.

The group said it had observed "various cases" of "excessive" use of police force, including “inappropriate and unjustified use of batons” against people “who posed no risk."

But Spanish judge Fernando Grande-Marlaska defended the police action and warned that demonstrators could face six-year prison sentences for their involvement in the riots.

Miquel Buch, Catalonia's pro-independence interior minister, said "This kind of violence is unprecedented in Catalonia ... these people are not separatists."

Tourists also felt the turmoil on Friday after cruise operators diverted their ships to other ports, and those which had already docked in the port of Barcelona cancelled their passengers' excursions to the city.

Tourist attraction Sagrada Familia also closed its doors due to a protest outside the basilica.

Dozens of flights into and out of the region were cancelled due to the strike. Picketers also blocked roads to the border with France and elsewhere.

Commuter and long-distance train services were significantly reduced, and many shops and factories did not open for business.

Friday's violence erupted after former Catalan leader Carles Puidgemont handed himself in to Belgian authorities, after Spain issued a new warrant for his arrest.

Mr Puigdemont – the former president of Catalonia – has been living in self-imposed exile in Belgium to avoid charges of sedition against the Spanish region, as well as misuse of public funds.

The charges were brought against him by prosecutors for his role in Catalonia’s failed unilateral declaration of independence in 2017, after which he fled the country.

His office said that he had “in the company of his lawyers, voluntarily appeared before Belgian authorities”.

Spain's interim prime minister, Pedro Sanchez, said authorities would prosecute radicals who rioted this week while ensuring that peaceful protests can continue.

"Those who break the law have to answer for their deeds sooner or later," Sanchez told a press conference in Brussels, where he was attending a European Union summit.

Additional reporting by Reuters and Associated Press