Kim Jong-un Demands More North Korean Nuclear Tests

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North Korea's leader Kim Jong-un has continued to stoke rising tensions on the Korean peninsula by calling for further nuclear tests, according to a report from state-run news agency KCNA on Friday.

The report said the remarks were made while Kim watched a ballistic missile test launch, likely referring to North Korea's launch of two short-range missiles from the eastern port city of Wonsan on Thursday, which flew 500 km (300 miles) and landed in the sea.

"Dear Comrade Kim Jong-un said work… must be strengthened to improve nuclear attack capability and issued combat tasks to continue nuclear explosion tests to assess the power of newly developed nuclear warheads and tests to improve nuclear attack capability," KCNA reported.

The North Korean leader was quoted in state media earlier in the week as saying his country had miniaturized nuclear warheads to mount on ballistic missiles.

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Tensions have increased rapidly on the Korean peninsula after the North conducted its fourth nuclear test in January and fired a long-range rocket last month leading to the UN Security Council to adopt a new sanctions resolution.

Conducting more nuclear tests would be in clear violation of UN sanctions which also ban ballistic missile tests, although Pyongyang has rejected them. North Korea has a large stockpile of short-range missiles and is developing long-range and intercontinental ballistic missiles (ICBMs).

In an interview with VICE News published this week, Victor Cha, a US representative in six-nation nuclear disarmament talks with North Korea in 2005 and former director for Asian affairs on the National Security Council, said he believes it is now too late to convince North Korea to give up its nuclear arms.

"As much as we have wanted over the past 25 to 30 years to focus our negotiations on getting them to give up their nuclear weapons, I don't think they're going to give up their nuclear weapons anymore," Cha said.

South Korea's Unification Ministry spokesman Jeong Joon-hee said: "It's simply rash and thoughtless behavior by someone who has no idea how the world works," when asked about Kim's comments.

UN Secretary-General Ban Ki-moon called on Pyongyang to "cease destabilizing acts," adding that Ban remained "gravely concerned" by the situation.

In China, North Korea's most important economic and diplomatic backer, the country's top newspaper, the People's Daily, urged all sides to be "patient and brave," show goodwill, and resume the talks process.

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South Korea said it did not believe that North Korea had successfully miniaturized a nuclear warhead or deployed a functioning intercontinental ballistic missile.

The US Defense Department said this week it had seen no evidence that North Korea had succeeded in miniaturizing a warhead.

However, Admiral Bill Gortney, the officer responsible for defending US air space, told a US Senate panel on Thursday it was "prudent" for him to assume North Korea could both miniaturize a warhead and put it on an ICBM that could target the US.

"Intel community gives it a very low probability of success, but I do not believe the American people want (me) to base my readiness assessment on a low probability," he said.

North Korea has issued nearly daily reports in recent days of Kim's instructions to fight South Korea and the US as the two allies began large-scale military drills.

North Korea called the annual drills "nuclear war moves" and threatened to respond with an all-out offensive. Kim last week ordered his country to be ready to use nuclear weapons in the face of what he sees as growing threats from enemies.

The US and South Korea remain technically at war with North Korea because the 1950-53 Korean War ended in a truce instead of a peace agreement.

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