Ikaika Erik Kang, 34, continued to serve in the Army for years after expressing support for ISIS

A US Army soldier who was pictured kissing the ISIS flag has pleaded not guilty to supporting the jihadist group.

Ikaika Kang, 34, was arraigned in federal court in Honolulu, Hawaii, after a grand jury indicted him last week on four counts of attempting to provide material support to the group.

Court documents claim that Kang met with undercover FBI agents he believed were part of the Islamic State group.

He allegedly provided them with classified military information, a drone, military equipment and training in combat fighting.

Kang may suffer from service-related mental health issues that the government was aware of but neglected to treat, his defense attorney, Birney Bervar has said.

Bervar is seeking a mental health evaluation for Kang, whose trial was set for September.

In this combination of two images taken from FBI video, Kang kisses an Islamic State group flag, left, then puts the flag to his forhead, right, after allegedly pledging allegiance to ISIS

Kang's father Clifford has since said his son, who was was deployed to Iraq in 2011 and Afghanistan in 2013, may have been suffering from post-traumatic stress disorder

During the meeting with undercover agents, Kang pledged allegiance to ISIS and kissed an Islamic State flag, according to court documents.

'Kang's military training, weapons abilities and personal combat skills, coupled with his strong stated desire to kill people in the name of Islamic State, makes him one of the more dangerous criminal defendants to have been charged in this judicial district,' prosecutors wrote in a motion asking that be held without bail.

Kang, an air traffic control specialist with extensive military training in hand-to-hand combat, was arrested by the FBI on Saturday following a year-long undercover investigation.

The FBI said he swore allegiance to Islamic State leader Abu Bakr al-Baghdadi, made training videos for the extremist group and purchased a drone aircraft intended to help ISIS fighters in the Middle East evade enemy tanks in battle.

Ikaika Erik Kang was with the 25th Infantry Division at Schofield Barracks in Honolulu

Former soldier Dustin Lyles, a medically retired soldier, said Kang's arrest came as a shock and that he never heard Kang express support for the enemy while they were army bunkmates

Kang is also accused of trying to furnish ISIS with classified and other sensitive military documents that would have assisted the group in its combat tactics.

A former Army bunkmate said that Kang believed the moon landing was faked, questioned the assassination of President John F. Kennedy and thought the Sept. 11 terrorist attacks were an inside job coordinated by the U.S. government.

Kang and Dustin Lyles, a medically retired soldier, bunked together for a month in 2013 during military training. The two were friends for several years before Lyle left the Army and the two lost touch.

Lyles told The Associated Press that Kang's arrest came as a shock and that he never heard Kang express support for the enemy. They shared sleeping quarters, ate together and practiced mixed martial arts.

The FBI said Kang swore allegiance to Islamic State leader Abu Bakr al-Baghdadi (pictured)

'If I had known that then ... I wouldn't even have talked to him after that,' Lyles said.

Lyles said he and Kang debated about conspiracies, including that 9/11 was staged by the U.S. to spark wars in the Middle East.

Kang aspired to become a pro MMA fighter, Lyles said. Kang completed a course to become a tactical combat instructor to soldiers, according to an FBI complaint filed in court.

With help from a Veterans Administration loan, Kang purchased a condo in May 2016 in a tidy suburban complex about a 20-minute drive to Schofield Barracks, according to property records.

A judge previously granted the request for no bail.

In a separate case, a 22-year-old California man has been charged with attempting to support terrorism by allegedly using social media to promote the Islamic State group and offering to join the organization, according to court documents.

Federal prosecutors allege Amer Sinan Alhaggagi 'went so far as to meet with undercover agents on multiple occasions to plan a potential terrorist attack,' said a court filing unsealed Friday.

His defense lawyer told the San Francisco Chronicle that the allegations are baseless and stem from idle talk in late-night internet chat rooms.