By Alix Kroeger
BBC European Union reporter
Several hundred people have taken part in a silent protest in Antwerp, following a shooting spree by a gunman believed to have far-right sympathies.
The killer was able to buy a gun with relative ease
Two people - a pregnant Malian woman working as a nanny and the two-year-old white girl in her care - were killed.
A third, a woman of Turkish descent, was seriously injured but her condition is not said to be life-threatening.
The killings are all the more shocking because they took place in broad daylight, in the centre of Antwerp.
Kiki Vervloesem, a spokeswoman for the mayor of Antwerp, said the city was "devastated".
"There is always a little bit of tension" between communities, she said, but people felt "shocked and a little bit powerless".
The far-right Flemish nationalist party, the Vlaams Belang (Flemish Interest), has strong support in Antwerp. In 2000, it won 33% of the vote in local elections under its previous name, the Vlaams Blok.
"There is too much talk about what makes the difference between 'us' and 'them'," said Jozef De Witte, director of the Brussels-based Centre for Equal Opportunities and Opposition to Racism.
And he predicted that the Vlaams Belang could increase its share of the vote in local elections in five months' time.
"Local elections are about neighbourhood issues," he said, "and these issues - crime levels, the number of police on the streets - are addressed by the Vlaams Belang. And there is a certain fear that they will have more votes than they did six years ago."
The Vlaams Belang took 24% of the vote in the Flemish regional elections two years ago. It is kept out of government only by a "cordon sanitaire": an agreement by all the other parties in the assembly, who refuse to the party in a coalition.
Mr De Witte cautioned that a racial motive for the killings had not yet been definitely established.
If it is, it is the most serious of its kind in Belgium in recent months, but by no means the only one.
On Monday, skinheads in the city of Bruges beat up a black Frenchman. He is still in hospital in a coma. The cafe frequented by the skinheads has now been closed down.
A few months ago, a black man was attacked at a petrol station in Brussels, apparently because he had been slow to move his car away from the pump.
The shootings have also raised questions about Belgium's gun laws, which are currently under review. The suspected gunman, who is 18, bought his weapon - a hunting rifle - an hour before the first of his attacks.
Controls on the sale of hunting rifles are limited: purchasers must provide a piece of identification and give their age. Kiki Vervloesem from the mayor's office said it was "unbelievable."
"We are very concerned that people who are 18 years old can just walk into a shop and buy a gun and load it," she said.
Another demonstration in protest at the killings will take place in Antwerp in two weeks' time, on 26 May. But for now, the shootings have raised questions about race relations in Belgium: questions which may find their fullest answer at the ballot box in October.