HAMBURG — More than 10,000 protesters took to the streets of Hamburg again on Friday to vent their anger at the Group of 20 summit meeting and the global political and economic system.

And once again, they were met with a huge police presence — hundreds of additional officers were called in after clashes left at least 196 officers and dozens of protesters injured.

It started early in the day: There were sit-down protests under a rainbow display of umbrellas. Students marched, calling for social justice. And some people took to a fleet of rubber boats, demanding solidarity with refugees. Protesters were soon engaged in a cat-and-mouse game with the police, who lined city streets to block off the areas where gatherings were taking place.