Catalonia's pro-independence regional chief Quim Torra called for talks with Spain's central government on Saturday to try to defuse unrest triggered by the jailing of separatist leaders.
Barcelona suffered its worst night of disturbances in decades on Friday as masked youths blocked roads with blazing garbage bins and hurled rocks at security forces, who responded by firing repeated rounds of smoke grenades and tear gas.
Catalonia is a semi-autonomous region with some 7.5 million inhabitants who have their own language, parliament and flag. It is Spain's wealthiest region and Barcelona is the country's second largest city, drawing millions of tourists each year.
Radical youth group Arran called for a fresh demonstration at 6 p.m. (1600 GMT) against "police violence" and to call for the "freedom of all political prisoners".
Police said they feared renewed confrontations and advised shopkeepers in the city centre to close during the protest.
Torra told reporters this week's violence did not reflect the peaceful nature of the traditional Catalan independence movement. "We urge the acting prime minister of the Spanish government to sit at a negotiating table to talk," he said.
"Violence has never been and will never be our way," he said.
Police said they arrested 54 people on Friday, the fifth day of clashes which were sparked by Spain's Supreme Court handing down lengthy prison terms to nine Catalan leaders who staged a banned referendum on independence in 2017.
Independence is a highly divisive issue in Catalonia, with a poll in July showing backing for secession at its lowest level in two years, with 48.3% of people against and 44% in favour.
Torra, who earlier this week said Catalonia should hold a new vote on independence within two years, said on Saturday the will of the people would be respected: "We will go as far as the people of Catalonia want to go".
The Socialist caretaker government in Madrid did not immediately respond to Torra's call for talks, but the opposition conservative People's People (PP) dismissed the idea.
"It is not time to call for dialogue, it is time to enforce the law and the Constitution," the PP's Pablo Casado said. "When a violent minority attacks the critical infrastructures of the state it is not time to demand silence, but to demand order."
Barcelona's mayor Ada Colau, who does not support the secessionist movement, said Barcelona "does not deserve what we are living through", adding that pavements had been torn up and hundreds of plastic garbage bins torched in the unrest.
Three roads in the city remained closed on Saturday because of the damage, with some foreign visitors caught unawares by the chaos and shocked by what they saw.
"We got here and were like 'Oh God'. The street was on fire in front of the hostel," said Flynn Winstanley, 18, a winery worker from Margaret River in Australia.