CINCINNATI — There has been little public word about what has happened to an American college student detained in North Korea, as a new administration takes over one year later amid deep US concerns about the hostile country’s nuclear and missile development.

North Korea announced Jan. 22, 2016, it had detained Otto Warmbier, a 21-year-old University of Virginia student from suburban Cincinnati, earlier that month for alleged antistate crime.

Warmbier, who had visited North Korea with a tour group, was sentenced in March to 15 years in prison at hard labor after a televised tearful public confession to trying to steal a propaganda banner.

Such North Korean detentions of US citizens for offenses that might seem minor to outsiders — Warmbier said he wanted to take the banner home for a woman in Ohio who wanted to hang it in her church — are seen in Washington as having political motives, and Warmbier’s has come during a time of worsening tensions. The State Department calls the sentence ‘‘unduly harsh,’’ and spokesman John Kirby said in a statement that the department continues to work for Warmbier’s ‘‘earliest possible release.’’

Associated Press