A firework bomb has been thrown through the letterbox of D66’s headquarters in The Hague, triggering an explosion. The fire brigade was called shortly after 9pm on Thursday. A suspect has been arrested, the police reported.

People were inside when it happened but no one has been reported injured. “They were, however, terrified,” a D66 spokesperson told broadcaster NOS.

“It is not entirely clear where this comes from, but it is unlikely to be a coincidence that this happened to us,” a spokesperson told the Telegraaf. The extent of the damage is not yet clear. “Leave our people alone,” they said.

In September last year, rioters from an anti-immigration demonstration smashed the windows at the same D66 offices, set fire to a police car, and tried to storm the parliamentary complex. Police made 37 arrests; experts linked the attack to football hooligans operating under the banner of the far-right group Defend Netherlands.