An explosion hit a synagogue in the Belgian city of Liège early on Monday in what authorities said was an antisemitic attack that caused damage but no injuries.

The explosion, which happened around 4 a.m. (11 p.m. Sunday ET), blew out the windows of the synagogue, as well as those of a building on the opposite side of the road, public broadcaster RTBF said.

The cause was not clear, but prosecutors said the case had been passed to federal authorities, which normally investigate incidents linked to terrorism or organized crime.

Belgian Interior Minister Bernard Quintin called the explosion “a despicable antisemitic act that directly targeted the Jewish community of Belgium”.

He said security measures around similar sites will continue to be reinforced.

Eitan Bergman, Vice-President of the Coordinating Committee of Jewish Organisations in Belgium (CCOJB), said the targeting of the synagogue was deeply shocking.

“Liège is home to a very small but vibrant Jewish community where I personally grew up. Today, the feelings among our community members are a mixture of sadness, worry and profound shock,” he told Reuters.

Police have cordoned off the largely residential street on the bank of the Meuse river opposite Liège city centre.

Federal prosecutors declined to give further details of the incident.