The president of Catalonia, Quim Torra, has blamed violent protests on “infiltrators” out to tarnish the image of the Catalan independence movement.
During a televised appeal for calm, Mr Torra for the first time condemned the violence that has seen burning barricades on the streets of Barcelona and petrol bombs thrown at police.
“The protest must be peaceful. We cannot allow a group of infiltrators or provocateurs to damage the image of a movement supported by millions,” Mr Torra said.
According to Spanish government figures, 194 police officers have been injured in three nights of demonstrations since the sentencing of key separatist politicians found guilty of rebellion for an illegal referendum on independence in 2017.
Mr Torra has been under increasing pressure as conservatives in Spain have urged the socialist government in Madrid to to use emergency powers to remove Mr Torra and impose direct rule.
Spanish interior minister Fernando Grande-Marlaska warned the Catalan leader that he was treading on thin ice if the violence continued.
“Mr Torra must decide if he wants to be the president of all Catalans or an activist,” the minister said, speaking after a meeting of a government crisis committee on the situation in Catalonia, chaired by prime minister Pedro Sánchez.
Protests on Wednesday night saw the number of arrests rise to 97 since the Supreme Court verdict was announced on Monday.
Cars and recycling containers were set ablaze in 45 places in Barcelona, according to the city council, while the Spanish National Police said officers had been attacked with acid and petrol bombs.
The UK Foreign Office has warned travellers to Barcelona and other areas of Catalonia of demonstrations that “occur with little or no warning”, and which “can escalate and turn confrontational”.