A German newspaper in the northern port city of Hamburg that reprinted caricatures of Prophet Muhammad from the French satirical magazine Charlie Hebdo was the target of an arson attack, according to police.

The regional tabloid daily, the Hamburger Morgenpost, was attacked on Sunday after it had splashed three Charlie Hebdo cartoons on its front page after the massacre at the Paris publication, running the headline "This much freedom must be possible!"

"Rocks and then a burning object were thrown through the window," a police spokesman told AFP news agency. "Two rooms on lower floors were damaged but the fire was put out quickly".

No one was hurt in the attack, which police said occurred at about 01:20 GMT. Two people were detained, while state security has opened an investigation, police said.

Hamburg police have detained two suspects of the attack.

German news agency DPA reported that the attack had occurred from a courtyard of the building and hit the newspaper's archive room where some records were destroyed.

It quoted a police spokeswoman as saying that the editorial team should be able to continue work in the building as the damage was relatively minor.

Connection to Paris attacks

Whether there was a connection between the Charlie Hebdo cartoons and the attack was the "key question", the police spokesman said, adding that it was "too soon" to know for certain.

Police declined to provide further information about the suspects.

No one at the Hamburger Morgenpost, known locally as the MOPO and which has a circulation of around 91,000, could immediately be reached for comment.

"Thick smoke is still hanging in the air, the police are looking for clues," the newspaper said in its online edition.

Two gunmen stormed the offices of Charlie Hebdo on Wednesday, killing a total of 12 people including the paper's editor, Stéphane Charbonnier. Both men were killed Friday in a standoff with police.

Several German newspapers had published the Charlie Hebdo Muhammad cartoons on their front pages on Thursday in a gesture of solidarity with the French cartoonists and in defence of free speech.