Ahead of the formal opening of the G20 Summit in the German city of Hamburg police and protesters have crashed.
It was learnt that the organisers had cancelled the march following the violence, but many demonstrators remained on the streets which has led to at least one person seriously hurt and was carried away covered by a foil blanket.
The United States President,Donald Trump and other world leaders have arrived in Hamburg for talks on a wide range of issues.
The clashes was said to began when police charged a group of anti-capitalist demonstrators at the march attended by thousands carrying banners with slogans such as “Welcome to hell” and “Smash G20”.
As a result, the police fired water cannon and pepper spray at masked protesters, who hurled bottles, stones and flares at police.
As that progresses, other protesters built makeshift barricades on streets leading to the setting ablaze of at least one vehicle while businesses had been damaged.
It was further learnt that up to 100,000 protesters are expected in Hamburg during the summit even though the police had earlier warned of possible violence confiscating a number of homemade weapons.
Mr Trump had met German Chancellor Angela Merkel and the pair were said to have spent an hour talking about North Korea, the Middle East, the conflict in eastern Ukraine and G20 issues, a German government spokesman said.
Last week Mrs Merkel said the G20 would focus on the Paris climate deal which the US has withdrawn from. But earlier she said that as the G20 host she would work to find compromises.
The summit will also see Mr Trump meet Russian President Vladimir Putin for the first time.
The meeting will take place at 14:45 local time (13:45 GMT) and last for an hour, Russian media report.