The offices of a German newspaper that reprinted Charlie Hebdo cartoons was the target of an arson attack early Sunday morning. 

Vandals threw rocks at the offices of Hamburg Morgenpost, which published copies of cartoons by the French satirical magazine at the center of a terrorist massacre in Paris on Wednesday. 

Many other German papers also printed the magazine’s cartoons in a show of solidarity for freedom of the press after the attack. 

According to police and the newspaper’s website, a firebomb was also thrown through the basement window of the building, setting fire to a number of archival files. 

A Fire Department spokesman said the fire was extinguished quickly, and that members of the newspaper’s staff will be able to return to work later Sunday morning.

While no one was in the building at the time of the attack, and there were no reported injuries, the building itself was damaged, and staff were badly shaken upon hearing of the attack. 

Two men “behaving suspiciously” in the area were arrested by police. German state security has begun an investigation into the incident. 

Hamburg Morgenpost’s management said it was too early to know whether the incident was related to the illustrations. 

The newspaper added that “smoke is still in the air” from the attacks.