Amid ongoing protests in Catalan, clashes erupted between protesters and police for the fourth night in a row on late Thursday and in the early hours of Friday in Barcelona.

Catalan separatists set fire to barricades and garbage containers and threw Molotov cocktails at police who fire foam and anti-riot rounds, according to reports.

The police in Barcelona were able to keep apart demonstrators from two rival rallies — one group marched in support of Catalan independence while the other was held by right-wing extremists. Protest marches were also held in Girona and Lleida, local media reported.

Earlier on Thursday, Catalonia’s separatist leader has vowed a new vote on secession from Spain within two years.

The semiautonomous region of 7.5 million people continues to grapple with protests following the decision by Spain’s Supreme Court to condemn nine separatist leaders to lengthy prison sentences on Monday.

Addressing the regional parliament, Catalan President Quim Torra denounced any violent tactics used by the demonstrators, calling the separatist cause a peaceful one. But he also pushed the case for forging ahead with the stalled secessionist drive in a region that has its own language, flag and legislature.

“We’ll return to the ballot box again on self-determination,” Torra told the Catalan parliament.

“If all parties and groups make it possible, we have to be able to finish this legislative term by validating independence”, Tora added.

Quim Torra’s comments in parliament on Thursday came as thousands of students took to the streets of Barcelona in protest over the Supreme Court’s decision to jail separatist leaders for their role in a 2017 referendum that Madrid deemed illegal.

Earlier on Monday, the Spanish Supreme Court sentenced nine Catalan separatist leaders to between nine and 13 years for sedition and misuse of public funds for their role in the 2017 independence referendum considered illegal by Madrid.

Vice President of the Catalan Parliament Oriol Junqueras was sentenced to 13 years prison for sedition and misuse of public funds, while politicians Raul Romeva, Dolors Bassa and activist Jordi Turull have all been handed a 12-year sentence.

In 2017, police and protesters clashed when Catalonia’s pro-independence leaders went ahead with a referendum ruled illegal by Spain’s constitutional court.

Three weeks after the banned 2017 vote, the Catalan parliament declared an independent republic. Madrid stepped in to impose its rule on the region, and several Catalan leaders fled or were arrested.

Carles Puigdemont, the former Catalan President, escaped trial after fleeing Spain in October 2017 before he could be arrested, along with four others.

The wealthy Catalan region is home to about 7.5 million people, with their own language, parliament, flag and also an 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.