Danes reacted with anxiety and dismay to this week's opening of a trial of four men charged with plotting to attack a newspaper that published caricatures of the Prophet Mohammed.

Danish public opinion sees the trial, expected to last at least two months, as an unwelcome spotlight on Denmark at a time when racial and religious sentiment in Europe is compounded with worries over economic problems and fears of a backlash to events in the Middle East.

The four men -- a Tunisian and three Swedes of Middle Eastern descent -- appeared in a court in Glostrup, outside the capital, and denied any part in the alleged planned attack on Jyllands-Posten.

The broadsheet published the cartoons of Mohammed in 2005, sparking protests by Muslims in Denmark and riots in Muslim countries.

Prosecutors said the men had plotted to open fire on the Copenhagen offices of Jyllands-Posten on the day Crown Prince Frederik was to visit the building for an award ceremony. The Jyllands-Posten has headquarters in Viby, a suburb of Arhus, but shares a Copenhagen office with the Politiken newspaper.

The prosecutors said the four intended to cause heavy loss of life but said they didn't think the prince was a target.

Police arrested the three Swedish citizens -- Munir Awad, Omar Abdallah Aboelazm and Sabhi Ben Mohamed Zalouti -- and Tunisian Munir Ben Mohamed Dhahri in December 2010.

Awad, Aboelazm and Dhahri were picked up at a flat near Copenhagen on Dec. 29, 2010, and Zalouti was arrested a day later after he crossed into Sweden and was extradited to Denmark.

Police said they seized a machine gun with a silencer, a revolver and 108 bullets and large quantities of duct tape when they arrested the men.

Prosecutor Gyrithe Ulrich told Danish television that "it is our perception that an unknown number of people were to be killed by shooting" during the award ceremony.

But, he said, there was no evidence that Crown Prince Frederik was an intended target.

The defendants have denied terrorism and illegal possession of weapons.

If convicted they could each face 14-16 years in prison.

Danish public opinion is concerned that Denmark remains a potential target for Islamic militants six years after the 12 cartoons depicting Islam and Mohammed appeared in the Jyllands-Posten. One of them showed Mohammed with a bomb in his turban.

The newspaper apologized as protests spread from Denmark to other countries but that didn't stop violence throughout the Muslim world the following year and sporadically since the publication.

Danes say they are concerned the trial refreshes a controversy that has been overtaken by events. A more pessimistic view is that the trial may fan sentiment aroused after events in Afghanistan, including the burning of the Koran at a U.S. air base which caused at least 41 deaths and 270 injuries. U.S. authorities apologized over the incident, which they said was inadvertent.

Incidents involving the burning of Danish flags and attacks on Danish embassies and establishments have been endemic since the cartoons' publication. But Danes say that, on the whole, Denmark's diplomatic ties with the Middle East remain unaffected.

Somali refugee Mohamed Geele was sentenced in 2011 to nine years in prison, to be followed by deportation, on the charge of trying to kill cartoonist Kurt Westergaard with an ax on Jan. 1, 2010.

Chechen asylum seeker Lors Dukayev was jailed for 12 years last year on charges of terrorism after he injured himself in Copenhagen with a letter bomb that was allegedly intended for Jyllands-Posten in 2010.