Dresden – Thousands of protesters formed a human chain in Dresden on Saturday, determined to stop neo-Nazis from exploiting the German city's painful history on the 65th anniversary of its deadly Allied bombing in World War II.

Heavy security including riot police was in place to prevent clashes between the two groups, and five police helicopters flew overhead to monitor the crowds.

Neo-Nazis have caused outrage in the past by comparing the 1945 bombing of Dresden to the Holocaust. Organizers of a far-right protest Saturday characterized it as a "mourning march."

Some 5,000 far-right supporters poured into the city, according to police, who limited them to a rally near a railway station rather than a march for security reasons after opponents staged sit-down blockades in streets nearby.

When that decision was announced, far-right demonstrators chanted "open the streets to the German youth."

Across the Elbe River, some 10,000 people joined hands to create a human chain symbolically protecting the restored city center from neo-Nazis, after the city mounted an unsuccessful legal challenge to block the far-right march.

"Dresden doesn't want them, and this gang doesn't belong here," Mayor Helma Orosz said.

The human chain helps to "make Dresden a fortress against intolerance and stupidity," and the anniversary provided a reminder of who started the war, she said.