Denmark’s PET security police said the suspects had planned to enter a Copenhagen office block housing several newspapers including offices of the daily Jyllands-Posten to “kill as many as possible of those around.”

Police found a machine gun with a silencer, ammunition and plastic strips that could be used as handcuffs, PET said. It did not say where the items had been seized.

“On the basis of the investigation, it is the PET’s assessment that the detainees were preparing a terror attack against a newspaper, which according to the PET’s information was Jyllands-Posten,” it said.

“It is likewise the PET’s view that the attack was due to be carried out in the coming days.”

Jyllands-Posten was the newspaper that first published the cartoons, provoking protests against Danish and European interests in the Middle East, Africa and Asia in which at least 50 people died.

Danish Justice Minister Lars Barfoed said those detained had a “militant background” and called the plan the most serious such attempt in Denmark so far.

Three of the detainees were Swedish citizens, the Swedish security police force SAPO said in a statement. Four were arrested in Denmark and one in Sweden.

The Nordic region, and especially Denmark, attracted the ire of militants across the world after the 2005 cartoons.

Both Denmark and Sweden have committed troops to US-led NATO forces in Afghanistan, while Danish soldiers were also stationed in Iraq after the US invasion.

Police uncovered a plot last year to attack Jyllands-Posten, and in January the creator of the most controversial cartoon escaped an axe attack by a man with Al-Qaeda links.

Last September, a man who was later found to have a map with the address of Jyllands-Posten’s headquarters in the city of Aarhus set off a small explosion in a Copenhagen hotel.

SAPO said the suspects were not linked to an attempted suicide bombing in Stockholm two weeks ago, when a man blew himself up as he was preparing to set off bombs, possibly at a train station or a department store, according to police.

In that case an e-mail — thought to have come from the bomber — was sent just before the attack, protesting against Sweden’s military presence in Afghanistan.

SAPO said police were investigating whether any of the latest suspects was preparing attacks in Sweden.