By Jack Kim SEOUL (Reuters) - North Korea's supreme court sentenced American student Otto Warmbier, who was arrested while visiting the country, to 15 years of hard labor on Wednesday for crimes against the state. Warmbier, a 21-year-old University of Virginia student, was detained in January for trying to steal an item bearing a propaganda slogan from his hotel in Pyongyang, North Korean media said previously. "The accused confessed to the serious offense against the DPRK he had committed, pursuant to the U.S. government's hostile policy toward it, in a bid to impair the unity of its people after entering it as a tourist," the state-controlled KCNA news agency reported, using the acronym for the Democratic People's Republic of Korea.] Human Rights Watch condemned the sentence handed down to the student from Wyoming, Ohio.