North Korea's recent rocket launch amounted to the test of a ballistic missile capable of carrying a half-tonne payload to the US west coast, the South Korean defence ministry said yesterday. The estimate was based on the analysis of an oxidiser container - recovered from the rocket's first-stage splashdown site - which stored red-fuming nitric acid to fuel the first-stage propellant. "Based on our analysis and simulation, the missile is capable of flying more than 10,000 kilometres with a warhead of 500kg to 600kg," a defence ministry official said. The estimated range of 10,000 kilometres covers the whole of Asia, eastern Europe and West Africa as well as Alaska and a large part of the US west coast, including San Francisco. South Korean defence officials said there was no confirmation the North had the re-entry technology needed for a payload to survive the heat and vibration generated by re-entry to the earth's atmosphere without disintegrating. Meanwhile, South Korean church groups displayed Christmas lights near the tense border with the North despite concerns about a violent response. Cross-border tensions have been high since the nuclear-armed North's rocket launch this month, which was widely condemned by the international community. The defence ministry, which allowed Christian groups to light the massive steel tower on a military-controlled hill in Gimpo, west of Seoul, said the tower would remain lit until January 2. The lights can apparently be seen several kilometres away in the impoverished North, which suffers chronic power shortages.