At least 20 masked men were seen throwing burning objects at a synagogue in the Swedish city of Gothenburg Saturday, according to multiple news reports.

"We do not know much more than there are several Molotov cocktails that have been thrown against the synagogue. These are bottles and gasoline,” a police officer at the site told CNN affiliate Expressen TV.

Police inspector Peter Nordengard told reporters the synagogue did not catch fire, and that the fire department extinguished flames from the objects.