Four men pled not guilty Friday as they went on trial in Denmarkover a suspected plot to massacre the staff of a newspaper that first published controversial cartoons of the Prophet Mohammed.

Sahbi Ben Mohamed Zalouti, Munir Awad and Omar Abdalla Aboelazm, all Swedish citizens of Tunisian, Lebanese and Moroccan origin respectively, along with a Tunisian national living in Sweden,Mounir Ben Mohamed Dhahri, face charges of "attempted terrorism."

Prosecutors say the four were plotting to "kill a large number of people" at the Jyllands-Posten daily's offices in Copenhagen when they were arrested on December 29, 2010.

Jyllands-Posten published a dozen cartoons in 2005 of the Prophet Mohammed that triggered violent and sometimes deadly protests around the world.

A machine gun with a silencer, a revolver, 108 bullets, reams of duct tape, and $20,000 were among the items found in the men's possession when they were arrested.

Danish police, who had been collaborating with their Swedish counterparts and had been wiretapping the men, swooped in just after hearing them say they were "going to" the newspaper office.

One of the two prosecutors, Henrik Plaehn, told the Glostrup district court that a ceremony celebrating the Sporting Newcomer of the Year at the newspaper was likely the target of the suspected plot.

In addition to a number of sports celebrities, Danish Crown Prince Frederik was present at the ceremony.

"It appears this event was the target," he said, according to Jyllands-Posten, stressing though that the prosecution did not know if the four accused had known the prince was there and did not think they had been after him.

Plaehn also argued that there was evidence the plot had links to Pakistan, but said he would provide more details later in the trial, which is set to last until June.

At least one of the men is known to have international ties: Awad has been arrested twice before abroad suspected of terrorist links, Sweden's foreign ministry told AFP last year.

He was arrested in Somalia by Ethiopian troops in 2007 and again in Pakistan two years later, when he was travelling with his wife, their two-year-old son and Mehdi Ghezali, a Swede who had spent two years at Guantanamo Bay.

Zalouti had also previously been arrested in Pakistan for entering the country illegally.

On Friday, the four accused all pled not guilty to the terrorism charge, but Dhahri did plead guilty to arms possession.

The prosecution has not yet said what penalty it will be seeking beyond a request that the four after serving their sentences be expelled from Denmark and never allowed to return.

According to public broadcaster DR, however, they all risked "a historically severe punishment," with up to 14 years behind bars.

Awad, Aboelazm and Dhahri arrived in Copenhagen on December 29, 2010 in a rented car from Stockholm and had, according to police, planned to storm the Jyllands-Posten offices located in the heart of the capital, and "kill as many people as possible".

The fourth man, Zalouti, was arrested the same day in Stockholm, and was later extradited to Denmark.

Jyllands-Posten has been the target of a string of attempted and plotted attacks, and remains a top target for Islamic extremists, Danish intelligence service PET said at the end of January.