By Daniel Rook Seoul
(SMH) -NORTH KOREA has fired another short-range missile and threatened fresh steps if world powers impose sanctions for its nuclear test, amid signs it may be preparing to launch a long-range missile.
The US said it was sending its North Korea envoy to the jittery region, where Chinese fishing boats were fleeing a sensitive part of the Yellow Sea in fear of naval clashes.
Communist North Korea, which has warned it could launch an attack on South Korea, vowed to respond to any fresh sanctions imposed by the United Nations Security Council, saying "self-defence measures will be inevitable".
"The world will soon witness how our army and people stand up against oppression and despotism by the UNSC and uphold their dignity and independence," North Korea's Foreign Ministry said.
Tension has run high since Kim Jong-il's regime said it tested a nuclear bomb on Monday for the second time and renounced the armistice that ended the Korean War in 1953.
North Korea test-fired another missile off its east coast on Friday, the sixth in a week, South Korea's Yonhap news agency said.
Two US defence officials said satellite photos suggested North Korea might be preparing to launch a long-range ballistic missile.
Vehicle movements at two missile sites resembled work done before North Korea fired a long-range rocket last month, said the officials, who did not want to be named.
With US and South Korean troops on high alert, US Defence Secretary Robert Gates was due to consult his counterparts from South Korea and Japan yesterday at a regional conference in Singapore.
Stephen Bosworth, the US special envoy on North Korea, and Deputy Secretary of State James Steinberg will head to Tokyo and later visit China, South Korea and Russia, the State Department said.
The countries were part of six-nation talks that agreed in 2007 to provide aid and security guarantees to North Korea in return for it closing its nuclear weapons program.
It quit the accord last month in protest after the UN Security Council unanimously condemned its long-range missile launch.
The Security Council has been discussing a potential resolution to condemn the nuclear test.
Mr Gates, en route to Singapore, accused the North of "very provocative, aggressive" actions. But he also tried to calm nerves, stressing that the US was not planning any military action.
Mr Gates said he was unaware of any unusual troop movements in North Korea, which has about 1.1 million soldiers, compared with 680,000 South Korean and 28,500 US troops south of the border.
"I don't think there is a need for us to reinforce our military presence in the South," he said. "Should the North Koreans do something extremely provocative militarily, then we have the forces to deal with it."
Professor Yang Moo-jin, of the University of North Korean Studies, Seoul, said: "The North may put its military on a war footing, test-fire a long-range missile and restart the plutonium reprocessing facilities at Yongbyon."