Police run over a barricade of burning cardboard boxes | Alex Caparrós/Getty Images Catalan president calls for end to Barcelona violence ‘Protests should be peaceful,’ says Quim Torra, following unrest in Catalan capital.

The president of Catalonia has called for an end to the violent protests that have rocked Barcelona since Monday, saying incidents of "vandalism" risk undermining the separatist cause.

"This has to stop right now," Quim Torra said in a televised address in the early hours of Thursday morning, Spanish media reported. "There is no reason or justification for burning cars, nor any other vandalism. Protests should be peaceful."

Torra's comments came after Spanish Prime Minister Pedro Sánchez on Wednesday called on the Catalan leader to "clearly condemn" the violent riots, which erupted in response the Spanish Supreme Court's decision on Monday to sentence 12 Catalan separatist leaders to up to 13 years in jail for their role in a failed bid for Catalan independence in 2017.

Demonstrations began hours after the verdict was announced on Monday, with some 10,000 protesters swarming Barcelona's airport, causing more than 100 flights to be canceled. At least 130 people were injured. Demonstrators in Barcelona on Wednesday set up blazing barricades, torched cars and launched projectiles at police.

Torra attributed the fires and burning of cars in the Catalan capital to "groups of infiltrators and provocateurs," who he said are causing "damage to the image of a movement of millions of Catalans."

"We cannot allow such groups who infiltrate and provoke to harm the image of a movement which counts millions of Catalans," Torra said.

Catalan unions have called on a general strike in the region for Friday.