Germany has marked the 60th anniversary of the bombing of Dresden, one of the most controversial Allied operations of World War II.
The message is supposed to be one of remembrance
The attacks killed about 35,000 people and ruined the city's heart, as ground forces closed in on the Nazi regime.
The commemorations culminated with 50,000 people lighting candles in an evening rally in memory of victims.
But there were also protests by far-right parties, who say the bombing should be seen as a war crime.
About 5,000 far-right supporters staged a protest march and police scuffled with left-wing protesters trying to disrupt their demonstration.
But the groups, led by the neo-Nazi National Democratic Party (NPD), have not so far managed to interfere with the official ceremonies.
Germany's chancellor earlier condemned their threats as a bid to rewrite history.
Ten thousand candles
Sunday began with a wreath-laying ceremony, attended by the ambassadors of Allied nations the US, UK, France and Russia and accompanied by solemn music from a brass quintet.
The NPD aims to portray Germany as a victim of the war
Evening events centred on the Church of Our Lady, which was almost completely destroyed in the raid but has now been rebuilt.
A cross made out of medieval nails that was rescued from the roof of Coventry cathedral in England - after it was bombed by the Germans in 1940 - is being presented to the Bishop of Dresden in a gesture of reconciliation.
Later up to 50,000 people, wearing white roses as a symbol of reconciliation, gathered in the city's historic centre and lit thousands of candles in memory of the dead.
Dresden's churches were to ring their bells to coincide with the moment the first bombs fell.
The BBC's Ray Furlong, in Dresden, says the message of the day was supposed to be one of remembrance for the dead - and hope that past wounds can be healed.
But there was a different mood as far-right groups gathered to hear speakers who said the bombing was a war crime and an act of genocide.
They later marched through the city carrying flaming torches, to the sound of loudspeakers playing music by Richard Wagner, Hitler's favourite composer.
But similar numbers of Dresden citizens protested at the far-right presence, and police were out in force to separate the two sides.
Chancellor Gerhard Schroeder spoke out against the far right.
"Today we grieve for the victims of war and the Nazi reign of terror in Dresden, in Germany and in Europe," he said in a statement issued in Berlin.
He pledged to oppose "these attempts to re-interpret history".
"We will not allow cause and effect to be reversed," he said.
NPD members in the Saxony state parliament, which meets in Dresden, caused outrage in January when they boycotted a commemoration of the liberation of the Auschwitz death camp.
Allied bombers took to the air on 13 February 1945 and rained bombs down on Dresden over two days. British planes made the initial two raids, followed by US aircraft.
They were acting on a request from Moscow. The city stood as an important railway and communications centre for Nazi forces resisting the Soviet advance from the east.
Officially, about 35,000 people died in the attacks. However, some historians suggest the number may have been greater, as German refugees from the east were arriving in the city and many of the dead were incinerated by the massive firestorm.
Some of the public buildings in the baroque city have been spectacularly restored, but much of its ruined historical heart has been replaced by modern buildings.