FILE PHOTO: A broken glass window of the Imperiale Marhaba hotel is seen after a gunman opened fire at the beachside hotel in Sousse, Tunisia June 26, 2015. REUTERS/Zoubeir Souissi

TUNIS (Reuters) - The trial of 26 people accused of involvement in a 2015 militant attack on a Tunisian beach resort which left 38 people dead opened on Friday, but was quickly adjourned after lawyers on both sides sought more time to prepare.

Most of the defendants face charges including homicide and forming a terrorist group in connection with the attack in Sousse, in which an Islamic State militant gunned down mostly British tourists before being shot dead by police.

The defendants also include six security force personnel accused of failing to help people in danger.

“We called for a postponement to study the legal files and minutes,” said Akram Barouni, who is representing one of the victims’ families.

“The lawyers ... hope the proceedings can be carried out in the best conditions in order to reveal the full truth and guarantee the rights and compensation for those affected,” he said.

Lawyers representing some defendants asked for their clients to be released from prison, saying they were not materially implicated in the attack.

“The defendants have been subjected to threats, torture, physical and moral violence,” said Salha Ben Farah, a lawyer for three of the accused. “They have no direct or indirect relationship with the perpetrator.”

Fourteen of the defendants are in detention. They were transferred from prison to a terrorism court in Tunis for the start of the trial on Friday, under tight security.

A British inquiry in February found that Tunisian security forces let down the Sousse victims by delaying their arrival on the scene.