The president of Spain’s Catalonia region, Quim Torra, has called for an immediate halt to violence, as protests continued into a fourth day.
“We condemn violence… This has to stop right now,” Quim Torra said. He later said he would push for a new referendum on Catalan independence.
Protesters clashed with riot police, days after nine separatist leaders were jailed for their role in a failed push for independence.
Ninety-six people have been hurt.
Demonstrators were detained in Barcelona, Lleida, Tarragona and Girona on Wednesday night as the protests spread across Spain’s north-east region.
Protesters have reportedly been using an app known as Tsunami Democràtic, which directs them to protest sites in Catalan cities.
The Spanish authorities say they are investigating who is co-ordinating the disruption. Mr Torra blamed “infiltrators” but government spokeswoman Isabel Celaá described those instigating the violence as “co-ordinated young Catalans” whose actions were not improvised.
Barricades were set alight and petrol bombs thrown as riots gripped the centre of Barcelona.
Police released footage of a firework fired at one of the helicopters flying over demonstrators in Barcelona.
Thousands of people have joined a series of “marches for freedom”, which are set to converge in the Catalan capital on Friday.
Quim Torra’s statement
In a televised statement, Mr Torra said “We will not permit incidents like those we are seeing in the streets”.
“This has to stop right now. There is no reason or justification for burning cars, nor any other vandalism.”
Mr Torra, who advocates independence for Catalonia, was speaking after Spanish Prime Minister Pedro Sánchez had made a direct appeal to him to condemn the violence.
Speaking in the Catalan parliament on Thursday, Mr Torra condemned the long jail sentences handed down to leading separatist figures on Monday as a “direct attack on fundamental rights”.
He appealed to the prime minister to “face up to the conflict as democracies do – by speaking to and giving voice to the citizens”.
Reason for the protest
The protests began after nine pro-independence leaders were jailed for between nine and 13 years by Spain’s Supreme Court.
The separatists were convicted of sedition over their role in an independence referendum in 2017.
Another three were found guilty of disobedience and fined but not jailed. All 12 defendants denied the charges.
On Monday, thousands of protesters blocked roads to Barcelona’s El Prat airport, a major transport hub.
More than 100 flights were cancelled as demonstrators fought running battles with riot police at the terminal buildings.
Catalan nationalists have long complained that their region, which has a distinct history dating back almost 1,000 years, sends too much money to poorer parts of Spain, through taxes which are controlled by Madrid.
The wealthy region is home to about 7.5 million people, with their own language, parliament, flag and anthem.
In September, a march in Barcelona in support of Catalonia’s independence from Spain drew crowds of about 600,000 people, one of the lowest turnouts in the eight-year history of the annual rally.