SEOUL - North Korea said on Thursday it planned to carry out a third nuclear test and more rocket launches aimed at its "arch-enemy" the United States in response to tightened UN sanctions.
The announcement prompted a call for restraint from the North's sole major ally China and a warning from rival South Korea to heed the demands of the international community.
Following a UN Security Council meeting this week, the communist state hurled fresh invective at its US-led foes in a statement from its National Defence Commission, without specifying when the nuclear test might take place.
But it said the test -- which would follow detonations in 2006 and 2009 that were condemned around the world -- would be part of an "upcoming all-out action" that marked a "new phase" in the country's anti-U.S. struggle.
"We do not hide that the various satellites and long-range rockets we will continue to launch, as well as the high-level nuclear test we will proceed with, are aimed at our arch-enemy the United States," the commission said.
"Settling accounts with the U.S. needs to be done with force, not with words," it added in the statement, carried by the official Korean Central News Agency.
It did not elaborate on the meaning of "high-level". Some experts have predicted that the North's next test might be of a uranium bomb, rather than the plutonium devices it detonated on the two previous occasions.
Such a development would indicate it had mastered the sophisticated technology needed to produce highly enriched uranium (HEU).
"The statement reads like typical North Korean brinkmanship, and we can't definitely say a test is imminent," said Kim Yong-Hyun, professor of North Korea studies at Dongguk University.
"But it's highly possible that it will use HEU for the test when it happens," Kim said.
While declining to name North Korea, China's foreign ministry said "all relevant parties" with a stake in the Korean peninsula should "refrain from action that might escalate the situation in the region."