Belgian police on Wednesday detained 15 members of a radical Salafist Islamic group after they harassed passers-by in the city of Antwerp and shouted anti-Western slogans, police said.
The Sharia4Belgium activists distributed leaflets glorifying Islam and criticizing the Western way of life in a central street of the northern port city, Belgian news agency Belga quoted a police spokeswoman as saying.
"Organisers had made no request for a demonstration, which was therefore not authorised," said the spokeswoman.
"When officers asked the demonstrators to identify themselves they refused," she added. "This led to skirmishes but no one was injured."
The group was detained for causing a public disturbance and taken to a police station for identification and questioning.
They were released later on Wednesday but Antwerp Mayor Patrick Janssens has decided to fill a complaint against Sharia4Belgium because, he said, he wants public order to be respected in his city, he said.
Sharia4Belgium wants Islamic law to be introduced in Belgium, whose second city of 480,000 inhabitants has a large Muslim community, mainly from Turkey and Morocco, and one of Europe's biggest Jewish Orthodox communities.