Officials in Hamburg have confirmed that around 500 police officers were injured in clashes during the G20 summit.
Three major marches took place as world leaders arrived in the German port city, with several smaller clashes turning violent.
Many of those injured were hit by glass bottles and other small items, while officers tried to push away protesters with tear gas and water cannons.
Hartmut Dudde, the head of operations for Hamburg police confirmed that a total of 476 officers were injured over the four days covering Thursday to Sunday (6-9 July) out of a total of 20,000 officers deployed.
Officials made 186 arrests in what was the largest police operation in Germany since the Second World War.
German president Frank-Walter Steinmeier visited some of the injured officers at hospital, he said: "We must ask ourselves as democrats whether a few violent protesters can keep countries such as Germany from holding such international meetings."
Meanwhile the German justice minister Heiko Maas called for better European security checks, he said: "Extremism cannot have any place here, no matter what the motives are. Those who support unrestrained violence will also have to be held responsible.
"A large proportion of the violent extremists travelled to the G20 from other European countries. We should respond with more co-operation in the fight against extremists."
Chancellor Angela Merkel has been criticised for choosing a city, the second-largest in Germany, as the base for this year's G20 summit. In recent years, more remote locations have been chosen by nations in a bid to cut down on large-scale protests.
Dudde admitted that even after 18 months of planning, the scale and ferocity of the protests had taken authorities by "surprise." The German police officers' union GdP criticised small blocs of extremists who had been intent upon "hijacking peaceful demonstrations by tens of thousands of people to deliberately attack."
Donald Trump praised Merkel for hosting the summit as well as the efforts made by police, he said: "The #G20Summit was a wonderful success and carried out beautifully by Chancellor Angela Merkel. Thank you! Law enforcement & military did a spectacular job in Hamburg. Everybody felt totally safe despite the anarchists."