Police have clashed with protesters in the German town of Garmisch Partenkirchen just hours before a meeting of G7 leaders is set to begin at a nearby hotel.
Police responded with pepper spray when a small group attempted to break through their cordon.
At least 3,500 demonstrators converged on the small Bavarian town, where they have demanded action on a number of issues including climate change, poverty and globalisation.
Some 17,000 German police officers have been deployed around the summit site in the Bavarian Alps with another 2,000 Austrian officers on standby across the nearby border.
German Chancellor Angela Merkel will welcome the leaders of the United Kingdom, Canada, France, Italy, Japan, the United States and the European Union on Sunday.
The main issues on the G7 summit agenda are climate change, the fight against pandemics, turmoil in the Middle East and the recent upsurge in violence in Ukraine.
The world economic recovery and Greece’s unresolved debt standoff with the IMF and eurozone creditors are also set to be discussed.
This will be the second summit of industrial nations without Russia, who have been excluded since the country’s annexation of Crimea last year.