US Secretary of State Hillary Clinton has warned North Korea against carrying out a missile launch. Mrs Clinton, who is in Japan on her first trip abroad as President Barack Obamas chief diplomat, said such a launch would hurt relations with the US. But Pyongyang says it has the right to "space development" - a term it has used before to disguise a missile test as a satellite launch. Mrs Clinton added that the hermit kingdom would have to make the first move to improve its relationship with the US by ending its nuclear programmes. Reports in South Korea say Pyongyang has been preparing to test its longest-range Taepodong-2 missile, which is designed to reach as far as Alaska but has never flown successfully. Officials in South Korea have also been anticipating a short-range missile test near a disputed sea border where navies from the two countries have clashed in the past.