Protesters have battled police in the heart of Barcelona, setting up fiery barricades and hurling rocks at security forces on the fifth day of unrest following the jailing of Catalan separatist leaders.
The violence came after a day of largely peaceful demonstrations as more than half-a-million people flooded the streets of the Catalan capital to denounce the lengthy jail terms that have sent a shockwave through Spanish politics.
But as night fell, masked youths blocked a broad boulevard close to the city's police headquarters, setting fire to large garbage bins and throwing a hail of stones, cans and bottles towards massed lines of security forces in full riot gear.
Some onlookers described the scene as being "like a war zone".
Police responded with repeated volleys of foam bullets, smoke grenades and tear gas, which covered the area in thick, choking smoke.
Officials said there were clashes in at least four other towns and cities in Catalonia, Spain's wealthiest region in the far northeast of the country, as the pro-independence anger showed no sign of abating.
Spain's acting interior minister, Fernando Grande-Marlaska, said 207 police had been injured since Monday, with 107 police vehicles damaged and 800 bins burned.
Some 128 people have been arrested in the region over the past five days and Grande-Marlaska warned that the rioters faced up to six years in prison.
It is the worst such unrest Spain has seen in decades and the interior ministry sent police reinforcements to Barcelona to try to quell the chaos.
"This kind of violence is unprecedented in Catalonia ... these people are not separatists," Miquel Buch, the Catalan interior affairs chief and a member of a pro-independence party, told the TV 3 channel.
The day started with hundreds of thousands of people from across the region pouring into Barcelona to protest against the verdict by Spain's Supreme Court, which sentenced nine separatists to prison over a failed, 2017 secessionist bid.
Unions called a general strike and students boycotted classes for a third day running.
Factories were closed, more than 50 flights at Barcelona's main airport were cancelled and local transport ran reduced services.
Police said some 525,000 people joined Friday's marches.
Catalonia is a semi-autonomous region with some 7.5 million inhabitants who have their own language, parliament and flag.
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 per cent of people against and 44 per cent in favour.
