The official said that the soldier was arrested because of connections he had with the Islamic State group.
He said the soldier was with the 25th Infantry Division at Schofield Barracks in Honolulu.
No other details were available.
The official was not authorized to discuss the matter publicly and spoke on condition of anonymity.
FBI spokesman Arnold Laanui said that SWAT team special agents arrested 34-year-old Ikaika Kang on Saturday. Laanui said the FBI will have more information when a criminal complaint has been filed.
Laanui said Kang is scheduled for an initial appearance in federal court on Monday afternoon.
His military service record said Kang was an air traffic control operator at Wheeler Army Airfield. His rank was sergeant first class.
Kang enlisted in the Army in December 2001 just months after the Sept. 11 attacks. 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.
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