Brussels: A man threw a petrol bomb through the window of a mosque west of Brussels on Monday, killing the imam and injuring a second person, Belgian newspaper La Derniere Heure reported.
The newspaper quoted police as saying a suspect was detained after the attack in Anderlecht and a large crowd of people gathered in front of the mosque. Police were not immediately reachable for comment.
Belgium has a Muslim population of about 500,000 out of a population of nearly 11 million and there are occasional acts of violence between communities, particularly in areas such as Anderlecht.
Derniere Heure said the victim, 46, was treated by emergency services at the scene but died of smoke inhalation.
In December, a gunman killed seven people in the eastern city of Liege after detonating a hand grenade and firing rifle shots into a crowd of Christmas shoppers.