Violence has erupted on the streets of Barcelona for the sixth consecutive night, after the city's mayor pleaded for calm over the protests.
Protesters in the city have clashed with police every night since Monday - angry with the decision to jail pro-independence leaders for their role in Catalonia's failed attempt to secede from Spain two years ago.
On Saturday, Mayor Ada Colau said that Friday's violence had been the worst so far, and called on protesters to calm down, saying: "This cannot continue. Barcelona does not deserve it."
An estimated 500,000 people took the streets in the city on Friday night in a show of support for the pro-independence movement.
The protests soon turned violent as hundreds of masked people surrounded the police's headquarters - with clashes continuing late into the night.
So far, rioters have thrown petrol bombs, acid and concrete at the police, as well as setting hundreds of bins on fire and using nails to damage police vehicles.
Some protesters even threw fireworks at a police helicopter - but no serious damage was caused.
Police dressed in riot gear have fought back using rubber bullets, tear gas and water cannon while dressed in riot gear.
Officials estimate that more than 500 people have been injured during the violence, including both police and rioters, with 18 people still in hospital. One of them is believed to be in a serious condition.
According to Fernando Grande-Marlaska, Spain's interior minister, 101 police officers were injured during Friday's violence alone - and more than 250 police vehicles have been seriously damaged during the week's protests.
Mr Grande-Marlaska has asked Catalonia's president to condemn the violence and express support for the police.
Catalan leader Quim Torra has told protesters to stop using violence and respect the huge separatist movement in the region, whereas the vice president, Pere Aragones, criticised the police's aggressive tactics.
Mr Torra used a television address on Saturday to demand a meeting with Spanish Prime Minister Pedro Sanchez, in order to push his secession agenda and discuss freeing the people who were imprisoned on Monday, saying: "We ask once again the acting Spanish PM to set the date and time to sit with us at a negotiating table.
"Today this is more necessary than ever before."
Mr Sanchez's office responded saying he would enter into dialogue, so long as it is within the law.