Thousands of demonstrators converged in Geneva, Switzerland, on Sunday, to protest against leaders of the G7 group of rich countries ahead of the summit’s opening in a nearby town in France.

The three-day summit starting this Monday in the resort town of Evian-les-Bains, France, will see leaders discuss issues including the Middle East, Ukraine and global economic imbalances.

Most of the leaders will be arriving at Geneva Airport before making their way to Evian.

Clashes broke out between protesters and police near the United Nations headquarters in Geneva on Sunday, as protesters threw bottles, stones, pieces of cement and firecrackers at the police, who responded with tear gas and water cannons.

According to figures from Geneva police spokesman Alexandre Brahier, an estimated 20,000 people, including some 600 so-called “Black Bloc” militants, took part in the demonstration.

Officials said environmentalists and feminists were amongst the protesters who joined critics of imperialism, defenders of independent media, supporters of Palestinian rights and others in a lakeside park in Geneva for the march across town.

A violent standoff extended into the evening after a series of incidents – including a car set ablaze and a bank’s windows smashed, media reports said.

French and Swiss authorities deploy thousands of police

Swiss and French authorities say they have deployed thousands of police to provide security for the three-day summit. In France, authorities say they will deploy more than 13,000 police and gendarmerie officers to ensure security in the summit area just across the border. Over 800 French border control officers will be active, up from about 60 normally.

Besides the increased police presence, authorities have also blocked off roads, banned unauthorised gatherings and pledged financial support for businesses that could be hit by unrest.

Scores of businesses and shops in the resort French town have boarded up their shopfronts with wooden panels as a precaution.

One resident, Robin Hedz, lamented the “mess” and expressed bafflement about the “wood-wall everywhere”, while acknowledging the memories of the trail of damaged property at the summit over 20 years ago in 2003.

The G7 summit is the first major international gathering since the US and Israel launched the war on Iran on February 28.

Since then the war has disrupted the fragile stability in the Middle East and led to a blockade of the Strait of Hormuz, where some 20 per cent of global shipping passes, causing a rise in global energy prices.