Ambassadors from the U.S. Russia, France and Britain, key allies in the Second World War, attended a wreath-laying ceremony Sunday marking the 60th anniversary of the bombing of Dresden.

An official estimate puts the death toll from the two-day bombing campaign at 35,000. The number could be much higher, however, as many of the dead were reduced to ashes by the massive firestorm unleashed by British and U.S. aircraft.

Far-right politicians, neo-Nazis and some historians call the bombing of Dresden mass murder, committed just three months before the end of the Second World War.

A statue of German religious reformer Martin Luther stands in front of the ruins of the Frauenkirche in this March 13, 1967 picture. (AP file photo)

British historian Frederick Taylor says the city was strategically important, that its war-related industries were replenishing supplies for German troops fighting approaching Soviet forces.

Far-right activists who call the air raids a "bombing holocaust" featured prominently as the day's memorial events began.

Members of the National Democratic Party helped organize a march to draw attention to the victims. The party provoked outrage last month by walking out of a commemoration of the liberation of the Auschwitz concentration camp.

Clergy from Coventry Cathedral in England, gutted by German bombing in 1940, presented a cross to Dresden's Frauenkirche, or Church of Our Lady.

The baroque church was left in ruins for decades by East Germany's communist government as a war memorial, but its 10-year reconstruction is now nearly complete, thanks to donations from around the world.