Organisers called off a march on Sunday in Brussels that was meant to show defiance to last week's bomb attacks, after senior officials urged people to stay away to avoid putting further strain an over-taxed police force.
Belgium on Saturday charged three people with terrorism in connection with the attacks at the airport and on a metro train on Tuesday in which 31 people were killed, including three attackers, and hundreds wounded.
In the following days, police carried out a series of raids and arrests across the city and the government has maintained the security alert at level three, the second highest level.
Brussels Mayor Yvan Mayeur and Interior Minister Jan Jambon asked for the demonstration to be delayed for several weeks.
"Given the security level 3 and the capacity of the police, the interior minister and the mayor ask you to delay tomorrow's gathering," the mayor said on Twitter.
The organiser, Emmanuel Foulon, who is a spokesman at the European Parliament, said he fully understood that argument.
"The security of our citizens is an absolute priority," he said by email.
"We totally agree with the authorities' request to delay this plan for a later date. We in turn ask citizens not to come to Brussels this Sunday."
The march, which organisers had expected thousands to attend, was meant to start at the Bourse (stock exchange), which has become a focal point for expressions of emotion for the victims of the attacks.