SEOUL, South Korea -- North Korea threatened on Sunday to carry out a "new form" of nuclear test, a year after its third nuclear test raised military tensions on the divided Korean Peninsula and prompted the United Nations to tighten sanctions against the North.
The North's Foreign Ministry did not clarify what it meant by a "new form" in its statement, carried by the North's official Korean Central News Agency. But the U.S. and its allies have long suspected the country of trying to make nuclear devices small and sophisticated enough to be delivered by intercontinental ballistic missiles it was also developing.
Responding to the North's announcement, Cho Tai-young, the spokesman for the South Korean Foreign Ministry, said in a statement that "North Korea should bear in mind that if it ignores the stern demand from the neighboring countries and the international community and carries out a nuclear test, it will have to pay a price for it."
The U.N. Security Council last week warned the North that it could face more censure because of its missile tests in the past weeks that flouted Security Council resolutions banning North Korea from testing ballistic missile technology.
The most recent test took place Wednesday, when North Korea test-fired two Rodong midrange ballistic missiles. The projectiles flew 403 miles from mobile launching pads on the west coast and landed in the sea between North Korea and Japan, South Korean officials said.
North Korea "would not rule out a new form of nuclear test for bolstering up its nuclear deterrence," the North Korean statement Sunday said, and it accused the U.S. of "acting rashly" at the Security Council.
South Korea and international analysts have recently said that satellite imagery showed continuing activities at the North's nuclear and rocket test sites, but they reported no signs that a test was imminent.
North Korea is also running an uranium enrichment program, first unveiled in 2010, that officials and analysts in the region fear will provide the country with a steady supply of fuel for nuclear bombs. After the North's last underground nuclear test in February last year, analysts could not determine whether the North used highly enriched uranium for fuel.
North Korea said its recent missile tests were a justified reaction to the joint military exercises being carried out by South Korea and the U.S., which it said raised the danger of war.
In late February, inter-Korean tensions eased enough for the two Koreas to allow hundreds of elderly Koreans separated by the Korean War six decades ago to hold brief reunions.
But since then the North has resumed its harsh language, calling President Park Geun-hye of South Korea "ignorant" and "vulgar" after she attended a global nuclear security summit meeting in the Netherlands last week and joined President Barack Obama and Prime Minister Shinzo Abe of Japan in calling on North Korea to give up its nuclear weapons.