Four Swedish men went on trial in Denmark Friday on terrorism charges arising from an alleged plot to attack a newspaper that published satirical cartoons depicting the Prophet Muhammad – an issue that has inflamed Muslims' passions in the past.

Three Swedish nationals and a resident of Sweden pleaded not guilty at the start of their trial, in a courtroom outside Copenhagen. Three of the men were arrested in December 2010 while they were allegedly heading to the offices of the newspaper newspaper to carry out the attack. The other man was arrested in Stockholm the same day, and later extradited to Denmark.

Prosecutors say the men on trial had ties to militant Islamist groups and international terrorist organizations, and had planned to kill a large number of people at the newspaper.

Three of the defendants also pleaded not guilty to charges of illegal weapons possession.

In 2005 Jyllands-Posten published a dozen cartoons depicting the Prophet Muhammad that many Muslims found insulting. The incident triggered several violent and sometimes deadly protests around the world.