A firework bomb was thrown through the letterbox of the headquarters of the Dutch centre-left liberal party D66 in The Hague late on Monday evening, causing an explosion inside the building and triggering widespread political condemnation. A suspect was arrested approximately one hour after the blast, though police have not yet established a motive.

The attack took place just after 9 p.m. at the party's office on the Lange Houtstraat in the heart of The Hague, the seat of the Dutch government. Around thirty young people were inside at the time, attending a speaker event organised by Jonge Democraten, the party's youth wing. No one was injured, though those present were badly shaken by what one witness described as a "bizarrely loud bang." A window pane shattered and smoke filled the building; attendees evacuated to a garden at the rear of the premises via an emergency exit route established after a previous attack. Police erected barriers around the site and described the structural damage as light.

This was not the first time the office has been targeted. In September, rioters smashed the building's windows and attempted to push a burning container inside during the aftermath of an anti-immigration demonstration on The Hague's Malieveld that turned violent. Thirty individuals have since been convicted for their role in that incident.

D66 leader and prime minister Rob Jetten condemned Monday's attack as "a cowardly act of intimidation," adding that democratic participation in the Netherlands would never be silenced by violence. Rachelle Smook, chair of the Jonge Democraten, called the incident deeply troubling in a broader context. "Young people must be able to participate in democracy freely and without fear," she said. Leaders of several other parties echoed her alarm: the liberal-conservative VVD, the Christian democratic CDA, the green-left GroenLinks-PvdA, and others all condemned the attack, with GroenLinks-PvdA leader Jesse Klaver describing it as "a direct assault on our democracy and rule of law."

The incident comes against a backdrop of rising political violence and attacks on Jewish institutions in the Netherlands in recent months, heightening concern about the security of democratic life. With no motive yet confirmed and the investigation ongoing, the attack has prompted urgent questions about political intimidation and the safety of those who engage in public life.