A U.S. Army soldier stationed in Hawaii was arrested over the weekend on charges of supporting the Islamic State.

The FBI confirmed on Monday that agents arrested Sgt. Erik Kang, 34, an active duty air traffic control operator who served in Afghanistan and Iraq, following a yearlong undercover investigation.

Kang was charged with attempting to provide material support to ISIS militants, including combat training documents, Reuters reported. The FBI believed he was a "lone actor."

In an affidavit filed in federal court Monday, the FBI said Kang pledged allegiance to ISIS leader Abu Bakr al-Baghdadi to several federal agents posing as operatives with the militant group. The FBI said Kang then made training videos for the militant group.

Kang was also charged with attempting to provide ISIS with classified military documents in an attempt to aid jihadists in combat techniques. The FBI said attempts to deliver the materials to ISIS were unsuccessful.

Kang, who was ranked sergeant first class, was assigned to the 25th Infantry Division at Wheeler Army Airfield on the island of Oahu in Hawaii. Military records show he served in Afghanistan from July 2013 to April 2014 and in Iraq from March 2010 to February 2011.