Riot police stormed a building squatted by anti-capitalist protesters in London's Soho district on Tuesday, ahead of next week's Group of Eight (G8) summit in Northern Ireland, dpa reported. Hundreds of police were patrolling the streets in central London, after the Stop G8 group called for a "Carnival Against Capitalism." They raided the house, where around 20 Stop G8 protesters were reportedly holed up after a three-hour standoff. A banner reading "What if we smash the G8?" hung from one window. "Don't let them intimidate us. The carnival will of course go ahead as planned," the group wrote on its website, as it urged protesters to meet at London's busy Piccadilly Circus and Oxford Circus for a rush-hour "street party." "It's clearly undemocratic," said one activist who only gave his name as Phoenix. "This really smacks of restricting the right to peacefully protest." Businesses in London's wealthy West End had warned their staff in advance to take precautions and told them "not to dress like a hedge fund manager" on their way to work, the Financial Times reported. The group earlier made a map of London available online listing potential targets including banks, media and "dens of the rich." "Everyone respects the right to legitimate protest and I hope this will be a day without incident," said Ed Argar, the local Westminster City council member responsible for city management. World leaders including Russian President Vladimir Putin and US President Barack Obama are set to meet on Monday in Enniskillen, Northern Ireland for two days of talks. They will be protected by around 8,000 police. More protests are planned in Belfast on Saturday, one organized by the Irish Congress for Trade Unions and another by the IF (Enough Food For Everyone) Campaign, as well as in Enniskillen during the summit. The meeting will cover world free trade, the fight against tax evasion and corruption in the sale of commodities and land in poor countries. It will also focus on the civil war in Syria as well as the controversial nuclear programs of North Korea and Iran.