Catalonia is a semi-autonomous region with some 7.5 million inhabitants

Catalon fmr chief Carles Puigdemont has escaped trial after fleeing to Belgium

Bystanders fled to the safety of shop doorways as protesters met with riot police

Barcelona has been flooded with an estimated half a million angry demonstrators waving pro-independence flags as protests over the jailing of Catalan separatist leaders showed no sign of letting up on Friday evening.

While the vast majority of the rallies were peaceful, a few hundred masked youths clashed with Spanish police in the heart of the city late in the afternoon on Friday, blocking a broad boulevard with burning garbage bins.

Violent clashes escalated into the late evening on Friday, as radical Catalan separatists hurled rocks and fireworks at police, who responded with teargas and rubber bullets, turning the city centre into a chaotic battleground.

One elderly man appeared to have had enough of the unrest and boldly confronted masked demonstrators while waving what appears to be a baton, as the demonstrators set up street barricades around him.

The unrest was sparked on Monday as the Spanish Supreme Court decided to jail nine separatist leaders for their role in a 2017 independence referendum banned by Madrid and a short-lived declaration of independence.

A protester stands next to a burning barricade during clashes near police headquarters in Barcelona on Friday, October 18

Protester waves pro-independence flag, an unofficial flag used by Catalan independence supporters

A huge blaze rages in Barcelona as protesters clashed with police on Friday

An injured police officer is assisted by his colleagues on the fifth day of protests over the conviction of a dozen Catalan independence leaders

Man speaks with protesters during Catalonia's general strike on Friday

Barcelona has been flooded with an estimated half a million angry demonstrators waving pro-independence flags as protests over the jailing of Catalan separatist leaders roll into their fifth day

One elderly man appeared to have had enough of the unrest and boldly confronted masked demonstrators while waving what appears to be a baton

The masked demonstrators continued to set up street barricades around the old man

Some of the protesters even appear to cower away from the man as he lunges at them with the black baton

Hoards of young protesters went on the rampage near the police headquarters, igniting a huge blaze which sent plumes of black smoke into the air, as police fired teargas to disperse them.

Other fires raged near Plaza de Catalunya at the top of the tourist hotspot Las Ramblas, where hundreds of demonstrators rallied in defiance of the police, who tried to disperse them with water canon.

'Anti-fascist Catalonia!' they roared. 'The streets will always be ours!'

Bystanders fled to the safety of shop doorways as police vans tried and failed to clear the road and police in full riot gear fired smoke grenades towards the rioters.

A crowd of protesters hurled stones and cans at police, and dragged large garbage bins to the middle of a main city boulevard, and set them ablaze. Police vans tried but failed to push people back onto the pavements.

Silhouettes of Striking Catalan pro-independence activists is seen against burning containers during a protest

A protestor is seen holding a Spanish police gas canister during a protest on Friday

Fires burn following an evening of rioting as a general strike is called after a week of protests over the jail sentences given to separatist politicians

Police estimated some 525,000 people joined the marches as the violence escalated on Friday

El Pais newspaper photojournalist Albert Garcia seen being detained by Spanish police

Spanish Police in the streets of Barcelona as clashes break out on the fifth day of protests

Scores of police vans could be seen fanning out around the streets, their sirens screaming as the regional police warned people in a message in English on Twitter 'not to approach' the city centre.

Earlier, many thousands of 'freedom marchers', who had set out to walk from five regional towns on Wednesday, arrived in Barcelona wearing walking boots and carrying hiking poles.

The rally coincided with the general strike, prompting the cancellation of 57 flights, the closure of shops, business and several top tourist attractions, and slowing public transport to a trickle in a region that accounts for about a fifth of Spain's economic output.

Activists also cut off Catalonia's main cross-border highway with France.

The ground is littered with debris as protesters throw objects during clashes near the police headquarters in Barcelona

Police officers intervene during unruly protests in Barcelona on Friday evening

Anti riot police pictured during clashes with Catalan pro-independence protesters in Barcelona

Fires burn in the city following an evening of rioting as a general strike was called

Silhouette of a man as fires burn in Barcelona following an evening of disruption and unrest

Fires burn following an evening of rioting as a general strike was called after a week of protests

Roads leading into the city were packed as marchers from across the region joined a mass rally against this week's verdict by Spain's Supreme Court, which sentenced nine separatists to jail over a failed, 2017 secessionist bid.

The ruling set off the worst sustained street violence Spain has seen in decades, with anger running high in Catalonia. Unions in the wealthy region called for a general strike on Friday and students boycotted classes for a third day running.

Police estimated some 525,000 people joined the marches.

Spanish interior minister Fernando Grande-Mariaska warned: 'Throughout this week there have been violent incidents in Catalonia. They have been organised by groups who are a minority but are very organised.

'Their actions will not go unpunished.'

Protesters throw objects close to a burning barricade near the police headquarters in Barcelona on Friday

A Catalan pro-independence protester throws a stone during clashes with police

Protesters wave the Estelada pro0 -independence flags during a demonstration in Barcelona

An elderly man confronts masks demonstrators on the fifth day of protests over the conviction of a dozen Catalan independence leaders in Barcelona

Police fire a weapon to disperse the crowds during a mass general strike in Catalonia on Friday

Riot police stand next to a flaming barricade as mass protests ravage the city

Police officers stand in front of fire as protesters call a general strike following a week of unrest of the jail sentences given to separatist politicians by Spain's Supreme Court

Police officers run past burning barricades on the fifth day of protests over the conviction of a dozen Catalan independence leaders

The interior ministry has dispatched police reinforcements to the Mediterranean city, which is a major tourist magnet, and warned that troublemakers would be swiftly dealt with.

'Throughout this week, as you well know, there have been violent incidents in Catalonia. They have been organised ... by groups who are a minority but are very organised,' Interior Minister Fernando Grande-Marlaska told a news conference. 'Their actions, as we have already said, will also not go unpunished.'

Pro-separatists set off on foot from across the region on Wednesday and flowed into Barcelona throughout the day, many with flags draped over their shoulders.

Locals applauded as the marchers strode past chanting 'freedom for political prisoners'.

Protesters set up a barricade as thousands of people take part in one of the so-called 'Marches for Freedom' in Barcelona

Police officers arrest a young protester during a mass demonstration organised by separatists

Protesters face police members as they take part in one of the so-called 'Marches for Freedom' in Barcelona on Friday

Protester drapes himself in the Estelada, an unofficial flag typically flown by Catalan independence supporters

'We have always been peaceful people, but you get to a point where you get treated in such a way that people are getting angry,' said Carlota Llacuna, a 19-year old student from the Maresca region near Barcelona. 'They put our leaders in prison.'

One of the main ringleaders, Catalonia's former chief Carles Puigdemont, has so far escaped trial after he fled to Belgium in 2017 when the independence drive was thwarted.

Spain this week renewed its bid to get him extradited and he was briefly detained by Belgian police on Friday before a judge ordered his release pending a decision on the Spanish arrest warrant. A court is meant to hear the case on Oct. 29.

Several main streets in Barcelona were closed to traffic because of Friday's marches, while regional trains and the city's metro were running on a reduced timetable.

Barcelona's main landmark, the multi-spired Sagrada Familia cathedral designed by Antoni Gaudi, was closed due to the protests, an official told Reuters.

Police advance towards rioters on the fifth day of protests over the conviction of a dozen Catalan independence leaders

Protesters set up a barricade as thousands of people take part in one of the so-called 'Marches for Freedom' in Barcelona

Protesters set up a barricade as thousands of people take part in the so-called 'March for Freedom'

Riot police stand guard during Catalonia's general strike in Barcelona on October 18

Riot police stand guard next to a burning barricade during Catalonia's general strike

The Spanish soccer federation (RFEF) said in a statement on that Barcelona's Oct. 26 home match against Real Madrid, which is known as 'el clasico' and is one of the biggest rivalries in world sport, had been postponed due to security concerns.

Barcelona's El Prat airport cancelled 57 flights on Friday, airport operator Aena said.

Barcelona town hall said 700 garbage containers had been set ablaze since protests began on Monday and estimated that the city had suffered damage totalling more than 1.5 million euros ($1.67 million).

In downtown Barcelona, many shops and luxury outlets were closed on the city's Paseo de Gracia, with blackened, charred patches a testimony to the nightly clashes that have raged since Monday.

'With these demonstrations bringing this large city to a halt, we are using Barcelona like a microphone,' said 23-year-old engineering student Ramon Pararada.

'It's all in reaction to the injustice,' he said.

Retired lawyer Jaume Enrich agreed, saying the court sentence was 'the straw that broke the camel's back.'

'Madrid is putting Spanish unity above everything, including basic rights,' he told AFP, wearing a badge saying 'No surrender'.

Nearby a banner fluttered reading 'There are not enough cages for this many birds.'

In an apparent effort to hamper the protesters, a Spanish judge ordered on Friday the closure of web pages linked to a pro-independence group, Democratic Tsunami, which has been deftly directing its followers to various demonstrations.

Protesters create a barricade as a general strike is called following a week of protests

Protesters stand behind trash containers used as barricades on the fifth day of protests over the conviction of a dozen Catalan independence leaders

Riot police detain a protester during Catalonia's general strike in Barcelona

A Catalan demonstrator runs during clashes at Catalonia's general strike in Barcelona

Police officers run past burning barricades on the fifth day of protests over the conviction of a dozen Catalan independence leaders in Barcelona

However, as soon as its site was shuttered, the group migrated its homepage to a new url, sidestepping the ruling.

Democratic Tsunami is a new, secretive group that emerged in September and has drawn thousands of followers on both its website and social media.

Although it says it is committed to non-violent protests, many young demonstrators have battled police over the past three nights in Barcelona in scenes reminiscent of the some of the urban unrest that has rocked France over the past year.

Catalonia is a semi-autonomous region with some 7.5 million inhabitants, who have their own language, parliament and flag. It is Spain's wealthiest region.

Independence is a highly divisive issue, with a poll in July showing backing for secession in the region at its lowest level in two years, with 48.3% of people against and 44% in favour.

A protester uses a sling shot to throw a firecracker at police during clashes in Barcelona

National police officers shoot rubber bullets to protesters during clashes