WASHINGTON (AFP) - The United States on Monday warned North Korea not to fire a long-range missile, saying it would worsen tensions after the communist states nuclear test. State Department spokesman Robert Wood said that a launch would be a clear violation of a UN Security Council resolution approved after Pyongyangs first nuclear test in 2006. The North, frankly, just needs to end this provocative type of behavior. Its only inflaming tensions in the region, Wood said. We want to see the North live up to its international obligations, Wood said. A South Korean defense official said earlier Monday that there were signs North korea was preparing to fire an intercontinental ballistic missile, in what would be its second such launch in as many months. An unrepentant North Korea appears to be pushing ahead with preparations to test-fire another long-range missile, defying global condemnation of its nuclear test, officials here said Monday. US Defence Secretary Robert Gates said Monday that North Korea could be preparing for a long-range missile test, but admitted that Pyongyangs intentions were not yet clear. We have seen some signs that they may be doing something with another Taepodong missile, Gates told a joint press conference with his Philippine counterpart Gilberto Teodoro. The secretive communist state was also said to be stepping up military drills near the border with the South, which is on heightened alert for a possible repeat of the deadly naval clashes seen in 1999 and 2002. Pyongyang has warned it would take additional self-defence measures in response to any tougher international sanctions and South Korea said Monday that a long-range missile launch appeared possible. We have detected signs that North Korea is preparing to fire an ICBM (intercontinental ballistic missile), a defence ministry spokesman told AFP. US and South Korean intelligence authorities are still analysing the information, he said. The North has moved the missile to a base in Dongchang-ri along its northwestern coast and a launch could take place in one or two weeks, South Koreas Yonhap news agency quoted an unnamed intelligence official as saying. US defence officials have also reported vehicle activity that suggests the North may be preparing to launch a long-range missile. We have seen some signs that they may be doing something with another Taepodong missile but at this point its not clear what theyre going to do, US Defence Secretary Robert Gates told reporters in Manila on Monday.