"We want peace, not war," and "No war with Iran," were among slogans brandished by marchers at the rally organised by the "Trump not Welcome" group.

The event passed off without incident with a number of children attending.

Organisers wanted to show their opposition to Trump's demand that Europe raise its share of defence spending and to his immigration policies which they dubbed "inhumane."

"We are against this logic where militarisation takes preference against the struggle against poverty, climate protection, migrant reception," explained a spokesperson for Ecolo J, a group of young Belgian ecologists.

Trump has been vociferous in his demands, already expressed from 2014 under predecessor Barack Obama, that US allies in Europe should make a greater contribution to the continent's defence and lift military spending to at least two percent of GDP by 2024.

Only eight of NATO's 29 member states -- including the United States, Britain, Greece and a handful of eastern European members, will meet the threshold as of this year.