German police have clashed with anti-capitalist protesters in Hamburg before the G20 summit.
The trouble came as Chancellor Angela Merkel hosted world leaders for informal meetings at the venue nearby, ahead of the two-day event.
Water cannons and pepper spray were used to disperse the demonstrators, some of whom attacked security forces with bottles and stones.
The police say they moved in after a hardcore ignored demands to remove their black hoods.
One protester was seen being struck as he fought with officers. At least one other was treated for injuries.
Security forces estimated earlier that of 100,000 demonstrators expected in the northern port city, some 8,000 were ready to commit violence.
Many believe that the G20 has failed to solve global issues.
The scenes will be an embarrassment for the German leader, who wanted to show the world that large protests are tolerated in a healthy democracy.
Merkel met US President Donald Trump for an hour on Thursday evening.