At the opening of their Amman trial, all six militants in custody pleaded not guilty before a Jordanian military tribunal to charges of firing rockets at two US warships docked in Aqaba Bay last August.
Of the 12 charged in the case, six are still at large.
The men, sporting short beards and dark blue prison uniforms, stood quietly with their feet cuffed in the dock during the hearing which lasted only 10 minutes.
A lawyer for the prime suspect, Mohammed Hassan Abdullah al-Sihly, a Syrian, 53, told the judges that his client did not carry out the attacks.
“We have nothing to do with those who fired on the frigate,” Ghaleb Suliaman told the three judge tribunal.
“We have no role in that at all. Those who fired the missiles are outside Jordan,” he said.