LONDON, England - June 17, 2008 - Anti-war protest leaders have accused the police of unprovoked brutality during protests in London to mark a visit by U.S. President George Bush.

Prominent campaigners said scenes of violence in Westminster reflected a growing authoritarian clampdown on the right to peaceful protest.

Members of the Stop the War Coalition criticized the Government for apparently allowing the president's security detail to enforce a protest-free "green zone" around his Downing Street visit.

They said protesters suffered injuries including head wounds, cuts and heavy bruising as they were beaten by police with batons at barricades between Whitehall and Parliament Square.

Veteran peace campaigner Walter Wolfgang, 84, said he was shocked by the unexpected violence.

He said: "Not only did some of the police behave brutally - they looked as if they enjoyed it. They used the batons without reason."

Human rights activist Bianca Jagger said protesters were attacked for attempting to exercise their rights.

Ms. Jagger said she narrowly escaped becoming caught up in the violence as she walked through the demonstration on Sunday.

Police arrested 25 people after 10 officers suffered minor injuries during the demonstration in Parliament Square.

Up to 2,500 people gathered to mark President Bush's farewell tour of London, which was surrounded by a massive security operation.