Riot police have swooped in on a number of protests in London, breaking up demonstrations and making 32 arrests. The Metropolitan Police said nearly 1,200 officers had been deployed.
More than a hundred riot police surrounded about 20 Stop G8 protesters who were believed to be holed up in a former police station in the Soho district. After a tense standoff, police forced their way inside the building and escorted several people out.
The Metropolitan Police said they had "a search warrant relating to intelligence that individuals at the address were in possession of weapons and were intent on causing criminal damage and engaging in violent disorder."
The raid came as some 150 protesters marched through the center of the city, banging drums in a "Carnival Against Capitalism."
"Don't let them intimidate us. The carnival will of course go ahead as planned," Stop G8 wrote on its website in response to the raids.
Police said they had also raided a second building in east London following reports of criminal damage, and had arrested three people.
Around 100 protesters also gathered outside the headquarters of oil company BP. Other demonstrators chanted "war criminals" outside the office of US defense aeronautics company Lockheed Martin and booed at the offices of US-based Citi bank.
There was also a standoff when police halted protesters attempting to enter the famous Fortnum and Mason department store.
A spokeswoman for the Home Office, Britain's interior ministry, said peaceful protest was "a vital part of democratic society, providing it is conducted within the law."
However, she added: "Rights to peaceful protests do not extend to violent or threatening behavior and the police have powers to deal with any such acts."
More protests planned
Leaders from the world's eight richest economies - the US, Britain, Canada, France, Germany, Italy, Japan and Russia - are due to meet June 17-18 at the Lough Erne luxury golf resort in Northern Ireland.
More protests are planned for Saturday in Belfast, one organized by the Irish Congress for Trade Unions and another by the Enough Food For Everyone IF Campaign.
Police are preparing a large security operation ahead of the summit, including bringing in 3,500 officers from the British mainland. A no-fly zone is also being imposed.
dr/kms (AFP, Reuters, dpa, AP)