Protesters have clashed with police at a largely peaceful anti-globalisation rally in the German city of Rostock.

Rocks, bottles and sticks were thrown at riot police, who used tear gas and batons to try to disperse the crowd.

A police spokeswoman described it as a "massive assault", but it only involved a small portion of the estimated 30,000 people who had joined the rally.

They are protesting against next week’s G8 summit of leading industrial nations in Heiligendamm, 25km (16 miles) away.

More than 160 groups of anti-globalisation activists, left-wing groups, students and anarchists had been taking part in the march.

Here to stay

The German authorities had warned in advance that there were serious concerns that far-left groups were planning violent attacks.

The authorities said that they would react quickly to any trouble and had deployed at least 13,000 police onto the city’s streets to oversee the proceedings.

Some shops had boarded up their windows as a precautionary measure.

Many of the protesters have travelled to Rostock from all over Europe and the majority have made camp by the harbour saying that they will stay put until the summit, which runs from 6-8 June.

The activist have pitched their tents in a large field where the main entrance bears the words: "No police and no neo-Nazis."

"It’s very important people all over the world come and protest against the politics of G8, which actually refer to all people of the world, although they are driven from the high elite in the G8 countries," said one protester.

"They actually use citizens of the world and the environment of the world as their playground to achieve more money and power."