Hamburg police deployed a water cannon and pepper spray on Thursday against thousands protesting the Group of 20 summit, breaking up the march on the eve of the global gathering in Germany’s second-largest city. As authorities tried to separate about 1,000 people belonging to a masked group and let the protest move forward, demonstrators tossed projectiles and set off fireworks. The already tense situation—with the crowd shouting: “all of Hamburg hates the police” —then turned chaotic as police responded with water and pepper spray. The march in the St. Pauli district, a bastion of left-wing activity for decades, was canceled by the organizers after moving only a short distance but thousands continued to wander the streets and police could be seen chasing some members of the Black Bloc, a group of black-clad militant anarchists. Demonstrators and police reported a unspecified number of injuries. “We were standing there and the police suddenly blocked the march—and at some point we heard a loud bang and everybody started running,” said Wolle, a 41-year-old Hamburg native, who declined to give his last name. “It’s really a shame. These are our tax funds.”  With helicopters hovering overhead and armored vehicles patrolling the streets, the center of the city of 1.7 million was largely at a standstill and many businesses closed their doors. Large demonstrations are also planned for Friday and Saturday, with German Interior Minister Thomas de Maiziere estimating that the number of protesters prepared to use violence stands at about 8,000. Many residents are feeling under siege. “It’s not that great that they held the meeting right here in Hamburg,” said Malte, a 29-year-old resident who said he planned to stay in the city. “Everything is in lockdown, you can’t even get in the subway.” As leaders arrived for the gathering hosted by German Chancellor Angela Merkel that begins on Friday, protest organizers are pledging “various and unpredictable mass resistance” as they make their way close to the summit venue. The “Welcome to Hell” organizers denounce the G-20 as a vehicle for global capitalism, “an assembly of bourgeois governments, torture states and warring military blocks reinforcing global exploitation,” according to the group’s manifesto. Police said some 30 protest events have been organized. A group called Block G-20 pledges to disrupt the meeting by using diversionary tactics against police, everything from marches to dancing and street theater. Primary targets for disruption are the summit venue, Hamburg’s City Hall and the Elbphilharmonie concert hall. Another organization said it will seek to shut down commercial activity in Hamburg’s port, an export hub for Europe’s largest economy that itself is reliant on global trade.