Six men accused of plotting to attack soldiers at Fort Dix pleaded not guilty Thursday as a federal judge promised to have the trial wrapped up by the end of the year.

Prosecutors said the trial will last about four weeks.

The men were arrested and charged last month with planning the attack. Authorities said they planned to use mortars, rocket-propelled grenades and guns in a raid on a New Jersey installation used mainly to train reservists.

Mohamad Ibrahim Shnewer, Serdar Tatar, and brothers Dritan, Eljvir and Shain Duka are charged with conspiring to kill military personnel, punishable by life in prison. Agron Abdullahu is charged with providing weapons to illegal immigrants, punishable by up to 10 years in prison.

The trial will take months to prepare because jury selection for such a high-profile case could be difficult and because the defense lawyers will need to review a mountain of evidence, including more than 1,000 audio-taped conversations, the judge said.

Calling it "an unusual case," Kugler said he would try to pave the way for a smooth trial by increasing security, allowing journalists to see evidence online as soon as it is introduced in court, and possibly blocking off streets around the federal courthouse in Camden.

The suspects have been held without bail in a federal detention center since they were arrested May 7. On Thursday, a different federal judge rejected Abdullahu's appeal of the decision to detain him as he awaits trial.

Investigators zeroed in on the men after an electronics store clerk told the FBI about footage of them firing assault weapons and screaming about jihad on a video they asked him to transfer to DVD. The men allegedly practiced firing weapons in the Pocono Mountains in Pennsylvania and made a deal, through a paid FBI informant, to buy fully automatic weapons.

Authorities said the six scouted out East Coast military installations to find one to attack but settled on Fort Dix largely because Tatar knew his way around from delivering pizzas to the base for his father's restaurant.

In the courtroom Thursday, the men waved and smiled at their relatives and the relatives gestured back. Ferik Duka, the father of three suspects, stage-whispered to each of his sons, "I love you."

Kugler said that the next time the suspects or their relatives tried to communicate there, they would be barred from the courtroom.