A petrol bomb attack on a Shia mosque in Brussels, Belgium has killed an imam and raised fears of sectarian violence among the country’s large Muslim immigrant population.

According to reports, the 46-year-old imam perished from smoke inhalation in the Rida mosque in the suburb of Anderlecht.

The imam was later identified as Abdallah Dadou, a father of four children.

The suspect is described by Belgian police as a 34-year-old Muslim -- but his motives at this point are unknown.

Jean-Marc Meilleur of Brussels' prosecutor's office, said in a statement: When they [police] arrived at the location they realized that there was indeed a fire but also that a person had been detained by the mosque occupants. It seemed that this person showed up and pulled out a knife and an axe, and that he spread flammable products, petrol we assume, in order to start a fire and threaten the people attending the mosque.

However, Belgian media reported that the suspect shouted something about Syria during the attack (in Syria, the Shia Alawite minority government of President Bashar al-Assad has waged a brutal crackdown against the country’s Sunni Muslim majority).

Azzedine Laghmich, an official at the mosque, told Agence France Presse (AFP) the suspect is a Salafist, an extremist form of fundamentalist Islam that often espouses a hatred of Shia Islam.

Isabelle Praile, a prominent figure in Belgium’s Muslim community, said the Rida mosque had been threatened by Salafists before.

AFP also reported that Rida is the largest Shia mosque in Brussels and had attracted about 100 people after the death to mourn the fallen imam.

The mayor of Anderlecht, Gaetan Val Goidsenhoven, has called for calm, citing that it is not only necessary to live side-by-side, but also to allow justice and the police to do their work.”

Joelle Milquet, Belgium's interior minister said she was very shocked by the events that have occurred.”

Belgium has about 900,000 Muslims, just under 10 percent of the population, many of them originally from Morocco and Turkey. In Brussels itself, one in four people is Muslim.

The overwhelming majority of Belgian Muslims follow Sunni Islam.

AFP noted that the last time an imam was killed in Brussels was in March 1989 when Abdullah Muhammad al-Ahdal, a Saudi and an imam in the Grand Mosque of Brussels, was shot to death. A pro-Iranian group based in Lebanon took responsibility for that murder, claiming al-Ahdal was too moderate, having rejected the fatwa order slapped against the author Salman Rushdie by Iran’s Ayatollah Khomeini.