The official said the soldier was arrested in regard to having connections with the Islamic State terrorist group.
The official was not authorized to discuss the matter publicly and spoke on condition of anonymity, like most CNN sources do, even when authorization isn't required.
FBI spokesman Arnold Laanui said on Monday that SWAT team special agents arrested Ikaika Kang on Saturday. Laanui said that more information will be forthcoming once a criminal complaint is filed.
This is a breaking story and no further details are yet available.