Warming up for G8

The marchers were warned not to approach within 500 metres of a city hotel, the venue for the Asia-Europe meeting (ASEM) of foreign ministers, which was to begin in the evening.

The leftists said on a website that they aimed to "disrupt" the meeting of the "totalitarian, capitalist" European Union which aimed to "exploit" Asian nations.

Saying they expected trouble, the authorities drafted in riot police from other states to flank the marchers.

Hundreds of protesters wearing balaclavas and protective clothing told reporters they would not let the police push them round. Other demonstrators wore colourful, carnival-like costumes.

On Sunday evening, police broke up an unregistered demonstration by 100 leftists in the city and briefly detained 53 after they tried to erect a barricade across a street.

Warm-up demos for the main event

The movement of leftists and anarchists said the Monday demonstration was round one of protests which would peak during the June 6-8 summit of the Group of Eight (G8) nations at the Baltic beach resort of Heiligendamm.

Leftists from Copenhagen and other European cities travelled to Hamburg to take part in the rally.

Germany currently occupies the presidency of both the EU and the G8. The ASEM meeting is the biggest gathering in Germany linked to Berlin's EU presidency.