Homeless people sleeping in parts of Brussels will be detained overnight if they refuse shelter, to protect them from sub-zero temperatures this week.

Temperatures in Brussels are set to fall to as low as -10 degrees Celsius (14 Fahrenheit) in the coming week, with strong winds adding a further chill factor.

The mayor of Etterbeek, a Brussels neighborhood home to many European Union offices, said he had asked police to take all homeless people to shelters even if they were unwilling to go.

"As a consequence, the mayor of Etterbeek has authorized, in case of absolute necessity, the detention of homeless people who are acting in a way that would endanger their safety by refusing shelter," Etterbeek council said in a statement.

The mayor of Brussels City, one of 19 councils that make up the greater Brussels region, said he had given similar orders to police and asked them to prioritize children sleeping outside.

Campaign groups estimate that there are more than 3,000 homeless people in the Brussels region.