SEOUL, South Korea — North Korea vowed Friday to retaliate if punitive U.N. sanctions are imposed for its latest nuclear test, and U.S. officials said there are new signs that the North may be planning more long-range missile launches.
With tensions rising, the communist nation punctuated its barrage of rhetoric with yet another short-range missile launch -- the sixth this week.
South Korea's Yonhap news agency said the latest test launch was a surface-to-air missile designed to defend against aircraft or other missile attacks. It said the missile was thought to be a version of the Russian SA-5.
Today, U.S. Defense Secretary Robert Gates warned North Korea that the United States would respond quickly if moves by the communist government threaten America or its Asian allies.
"We will not stand idly by as North Korea builds the capability to wreak destruction on any target in the region -- or on us," Gates told an annual international meeting of defense and security officials from Asia and the Pacific Rim.
Gates called North Korea's nuclear program a "harbinger of a dark future" but said he does not consider it a direct military threat to the United States "at this point."
The nuclear test and flurry of missile launches, coupled with the rhetoric from North Korea that it won't honor a 1953 truce ending the fighting in the Korean War, have raised tensions in the region and heightened concerns that the North may provoke a skirmish along the border or off its western coast -- the site of deadly clashes in 1999 and 2002.
But officials said the heavily fortified border remains calm, and Gates said the U.S. does not see the situation as a crisis warranting any more troops to augment the 28,000 U.S. forces already in South Korea.
North Korea remained strident.
"There is a limit to our patience," its Foreign Ministry said in a statement carried on the official Korean Central News Agency. "The nuclear test conducted in our nation this time is the Earth's 2,054th nuclear test. The five permanent members of the U.N. Security Council have conducted 99.99 percent of the total nuclear tests."
North Korea said it conducted the test in self-defense. It has asserted the U.S. is planning a pre-emptive strike to oust the regime of leader Kim Jong Il and warned it would not accept sanctions or other measures being discussed by the Security Council.
"If the U.N. Security Council makes a further provocation, it will be inevitable for us to take further self-defense measures," the Foreign Ministry said. It reiterated that it no longer sees the truce as valid, but it has made that claim in the past.
North and South Korea technically remain at war because they signed a truce, not a peace treaty, in 1953.