An improvised fire bomb was thrown at the offices of a German newspaper which reprinted cartoons of the prophet Mohammed from the French magazine 'Charlie Hebdo'.
No one was injured in the fire at the offices of the 'Hamburger Morgenpost'. The attack took place late on Saturday night.
The newspaper featured three 'Charlie Hebdo' cartoons of the prophet Mohammed on its front page on Thursday, together with the headline "This much freedom must be possible!"
Two young men who were acting suspiciously in the area were arrested and questioned but police said it was "too soon" to say whether the attack was connected to the publication of the cartoons. "There is no evidence, no claim of responsibility or other leads," a police spokeswoman told reporters.
The attack came at around 2.22am local time, when the offices were closed for the night. The perpetrators broke a window with a stone, and threw an "incendiary device" into the building.
The alarm was quickly raised and the fire brigade was able to put out the blaze with little difficulty. The only damage was to some files and back issues of the newspaper, which were burnt, and staff were able to resume work.
The 'Hamburger Morgenpost', or MoPo as it is affectionately known in Hamburg, has a circulation of around 91,000.