Catalonia's leader on Monday called for international mediation in the region's bid to declare independence from Spain, a day after violence and chaos erupted over a disputed referendum that left nearly 900 people injured in clashes with riot police.

Carles Puigdemont said the European Union should consider the independence issue as a regional problem and urged Spanish Prime Minister Mariano Rajoy’s government to accept mediation.

“This is not a domestic issue. The need for mediation is evident,” the Catalan president said.

Puigdemont said the regional parliament in the next few days will carry out the mandate to declare independence after the “yes” victory in the referendum.

Catalonia, an autonomous region in northeastern Spain that includes Barcelona as its capital, said 90% of those who voted Sunday favored independence.

Regional government spokesman Jordi Turull said 2.26 million people voted out of 5.3 million registered voters, a turnout of 42.3%.

Spain insists the referendum was illegal and invalid. The constitutional court had earlier suspended the vote, but local authorities went ahead with the balloting anyway.

Spanish Foreign Minister Alfonso Dastis said Monday he didn't consider the police response heavy-handed, saying it was "a matter of interpretation."

“I don’t think there was such a heavy hand, but in any case, they had to react,” Dastis said ahead of an Italian-Spanish forum in Rome. He said “some of the pictures are real, some of them are not real,” but police simply reacted when people were preventing them from doing what the courts had ordered.

Several European leaders called for restraint. EU chief Donald Tusk appealed to Rajoy to “avoid further escalation and use of force” while recognizing the independence vote as invalid. Several human rights organizations called for an investigation into the violence.

Chaos erupted shortly after the polls opened, with video showing Spanish police using batons, firing rubber bullets and roughing up voters. More than 890 civilians were treated for injuries, most of them not serious, according to Catalan regional health authorities.

Spain’s Interior Ministry on Monday raised the number of National Police and Civil Guard agents injured to 431 from 33, most from kicks, bites and scratches, but no one was hospitalized.

Catalan leaders accused Spanish police of brutality and repression while the Spanish government praised the security forces for behaving firmly and proportionately.

Rajoy was meeting Monday with ruling Popular Party leaders before seeking a parliamentary session to discuss how to confront the country’s most serious crisis in decades.

More:More than 800 injured in Catalonia when Spanish police crack down on independence vote

Rajoy, in a televised address Sunday, declared there was no independence vote and thanked the police for acting with “firmness and serenity.”

In an editorial, the Spanish newspaper El Pais blamed the Catalan government for Sunday’s “shameful” events but also criticized the Spanish government for its inability to tackle the crisis since it began about seven years ago. The newspaper said the day was “a defeat for our country.”

So far, the European Union, the United States and most international bodies have backed Spain in its stance against Catalonia.

Catalonia represents a fifth of Spain’s economy. Earlier polls consistently showed that while most of its 7.5 million inhabitants favored a referendum, they were roughly evenly split on independence from Spain.

Contributing: The Associated Press