The EU executive called again on Wednesday for the Spanish government and Catalan authorities to open dialogue to defuse the sometimes violent confrontation over calls for Catalonia's independence.
"It's time to talk," European Commission's First Vice President Frans Timmermans told the European Parliament as the EU legislature opened a debate on the situation.
Reflecting the cautiously balanced tone of a formal Commission statement on Monday after images of police violence against voters marked an unauthorised independence referendum on Sunday, Timmermans backed the legal position of Spanish Prime Minister Mariano Rajoy but also renewed a call for dialogue.
"Respect for the rule of law is not optional, it is fundamental," said Timmermans, the Dutchman who is deputy to the EU's chief executive Jean-Claude Juncker.
"If the law does not give you what you want, you can oppose the law," he said. "You can work to change the law, but you cannot ignore the law. It is fundamental that the constitutions of every one of our member states are upheld and respected."
"The regional government of Catalonia has chosen to ignore the law when organising the referendum," he said, before turning to urge restraint also on the conservative government in Madrid.
Describing Sunday's images of Spanish police clubbing women trying to vote as "saddening", he added: "Violence does not solve anything in politics ... However, it is of course a duty for any government to uphold the rule of law and this sometimes does require the proportionate use of force."
He insisted that the Commission saw the matter as an internal one for Spain: "That is why the Commission has called on all relevant actors to now move quickly from confrontation to dialogue. All lines of communication must stay open".
"It's time to talk. To find a way out of the impasse, working within the constitutional order of Spain."
Juncker, he said, was in contact with Rajoy and trusted the premier to resolve the crisis "in the spirit of dialogue".
The Commission has not responded to calls from the Catalan authorities to mediate, insisting it is a matter for Spaniards themselves.
Earlier on Wednesday, Spanish members traded accusations over whether leaders in Barcelona or Madrid were responsible for the crisis. At one point, one Spanish liberal lawmaker held up a copy of the post-dictatorship constitution, brandishing it at Catalan separatists and saying Catalans voted for it in 1978.
In the afternoon debate, leaders of the main parties in the Strasbourg chamber broadly echoed Timmermans' arguments.
The centre-right leader, Bavarian Manfred Weber, and the liberal leader, Flemish Guy Verhofstadt, both referred to their own origins to argue that strong regional identity and autonomy did not mean breaking up existing nation states.
"The irresponsible Catalan government is splitting the country," said Weber, an ally of German Chancellor Angela Merkel. He said it was up to Spaniards to resolve their problems and said the EU had neither the will nor the means to intercede.
Some lawmakers, however, said Brussels could to more to help.
