BARCELONA (Reuters) - Spanish police and militant elements in a thousands-strong crowd of protesters clashed in the streets of Barcelona close to police headquarters late on Saturday as a pro-independence demonstration by a direct action group turned violent.

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The protest began around 7:30 p.m. and as the crowd grew to around 10,000, according to police estimates, demonstrators threw a hail of bottles, balls and rubber bullets at officers, TV footage showed.

It was organized by CDR, a pro-independence pressure group that favors direct action and has cut railtracks and roads as well as trying to storm the regional parliament.

Police carrying shields and weapons and backed by some 20 riot vans charged the demonstrators in an attempt to disperse them, splitting the crowd in two along Via Laietana near the police HQ.

Reuters TV footage showed police armed with batons forcing their way through the crowd while demonstrators threw stones and flares. News channel 24h showed police grappling one-on-one with demonstrators, who fell back before reforming their lines.

Police dispersed some protesters through Gran Via, one of the city’s main avenues, where there were some baton charges as protesters ran, setting barricades in places.

Some projectiles were fired.

A Reuters photographer was hospitalized after being hit in the stomach by a rubber or foam bullet, while Catalan emergency services said medics treated four people, none of whom were seriously injured.

Further down Via Laietana, a major tourist avenue in central Barcelona, a Reuters reporter saw dozens of young demonstrators with their faces covered throw plastic bottles at a line of anti-riot police officers.

Protesters chanting “Catalonia antifascist” gathered at both ends of the avenue, cordoned off by dozens of police vans and officers, some equipped with weapons carrying rubber and foam bullets.

Local newspaper la Vanguardia said at least two protesters were arrested.