London: Hundreds of riot-police have surrounded a building occupied by anti-G8 protesters in central London, before a summit of world leaders in Britain next week.
The squatting activists had taken over the unused office block in Beak Street as a temporary base.
London's Metropolitan Police said it had a search warrant for the address.
"People inside the property...are free to leave but will be searched," the police said on Twitter on Tuesday.
The police operation came as around 150 protesters paraded through central London, banging drums in a "Carnival Against Capitalism" organised by the group Stop G8.
About 70 police in riot gear were at the scene of the protest and there were several scuffles between officers and demonstrators.