- North Korea's nuclear test "extremely worrying" for region, says Mike Chinoy
- U.S. has few viable options for dealing with North Korea
- Chinoy says Beijing is likely to be angered by test
Mike Chinoy is a former CNN senior international correspondent and served as CNN Beijing bureau chief from 1987 to 1995. He's the author of "Meltdown: The inside story of the North Korean nuclear crisis" and "The Last P.O.W."
Hong Kong (CNN)North Korea has pushed the button on its fourth underground nuclear test, claiming to have detonated a hydrogen bomb in the northeast of the country.