North Korean leader Kim Jong Un has promised to take "high-profile important state measures," the latest in a series of threats sparked by a tightening of United Nations sanctions, state media reported.

Kim spoke at a meeting of top security and foreign affairs officials, though the dispatch on Sunday in the official Korean Central News Agency did not say when the meeting took place. It did not elaborate on the planned measures, but Kim's remarks appeared to refer to a planned nuclear test scheduled to occur within the next few weeks.

The warning came one day after Pyongyang called the test "a demand of the people" following sanctions adopted by the Security Council last week.

The world body condemned North Korea's December 12 launch of a long-range rocket, and ordered the government to refrain from further tests. North Korea said that it will continue to develop rockets to counter what it calls US hostility.

"This fact proved once again that the [North] should defend its sovereignty by itself," state television said. "It became clear that there can be no denuclearisation of the Korean peninsula before the world has been denuclearised."

International isolation



North Korea is estimated to have enough weaponized plutonium for four to eight nuclear bombs, according to American nuclear scientist Siegfried Hecker, who visited the country's nuclear complex northwest of Pyongyang in November 2010.

But it remains unclear whether North Korean scientists have found a way to build nuclear warheads small enough to mount on a long-range missile. Experts say regular tests are needed to perfect the technique; North Korea has carried out two so far, in 2006 and 2009.

South Korean defence officials say North Korea appears ready to conduct a nuclear test in a matter of days. Satellite photos taken Wednesday show that over the past month, roads have been kept clear of snow; North Koreans may have been sealing the tunnel into a mountainside where a nuclear device would be detonated.

The US, South Korea and other countries have warned North Korea not to go ahead with a nuclear test, saying that would only deepen the country's international isolation.

After meeting with Chinese officials Friday, Glyn Davies, the US envoy for the North Korean nuclear issue, said a test would set back efforts to restart regional talks on the North's nuclear disarmament.