An active duty soldier based in Hawaii is accused of pledging allegiance to Islamic State, according to an FBI affidavit.
Ikaika Kang, 34, a sergeant first class in the US army, made an initial appearance in federal court in Honolulu. He was arrested on Saturday on terrorism charges.
Paul Delacourt, the FBI special agent in charge of the Hawaii bureau, said no documents made it to the Islamic State.
The 26-page affidavit from FBI Special Agent Jimmy Chen lays out details of the year-long investigation into the 34-year-old soldier.
Among the charges was that Kang copied military secret documents in 2015 and wanted to provide them to the organisation, according to the affidavit. It also said Kang admitted that he voluntarily pledged loyalty to Islamic State leader Abu Bakr al-Baghdadi.
This occurred on Saturday at a home in Honolulu, where he thought he was meeting an actual member of the organisation, the affidavit said.
They made combat training videos he believed would be taken back to the Middle East to help prepare the group's soldiers to fight American forces, according to the affidavit.
Kang, who received extensive combat training, also helped purchase a drone that he believed would help Islamic State soldiers escape from American tanks, the affidavit said.
Kang, a trained air traffic controller based at Hawaii's Wheeler Army Airfield, had his military clearance revoked in 2012 for making pro-Islamic State comments while at work and on-post and threatening to hurt or kill fellow service members.
His clearance was reinstated a year later after he completed military requirements.
However, the affidavit said the army believed Kang was becoming radicalised in 2016 and asked the FBI to investigate.
Kang enlisted in the army in December 2001. He served in Iraq from March 2010 to February 2011 and Afghanistan from July 2013 to April 2014. Kang was assigned to the headquarters of the 25th Combat Aviation Brigade.
Birney Bervar, Kang's appointed attorney, said after Kang's initial court appears that he still does not know much about the case. He said he only talked to Kang for a few minutes.