Moscow and Tokyo turned on North Korea yesterday following its veiled threat to test a nuclear bomb as South Korea dismissed the latest statement from Pyongyang as brinkmanship.

North Korea issued the threat ahead of US President George W Bush's arrival in Tokyo at the start of a six-day Asian tour to consult key allies.

A foreign ministry spokesperson in Tokyo expressed frustration with the Stalinist regime, calling for a "responsible and forward-looking response from North Korea toward the settlement of the issue".

Russian Deputy Foreign Minister Yury Fedotov demanded an end to "statements and actions, which would complicate the negotiated resolution of the problem".

Heads of state at a summit of 21 Pacific Rim nations which Bush will attend next week along with China's leader Hu Jintao are considering stepping up the pressure on Pyongyang after the Stalinist state promised a public demonstration of its nuclear capability.

However, efforts to coax North Korea back to multilateral talks to resolve the year-long nuclear crisis ended in failure at inter-Korean cabinet-level talks in the North Korean capital.

A North Korean foreign ministry spokesperson said Thursday Pyongyang would publicly display the "physical force" of its nuclear deterrent at a moment of its own choosing.

"When an appropriate time comes, the DPRK (North Korea) will take a measure to open its nuclear deterrent to the public as a physical force and then there will be no need to have any more argument," the spokesman was quoted as saying by the official Korean Central News Agency.

North Korea is known for ratcheting up tension to gain advantage ahead of delicate negotiations and South Korea said the statement appeared to be a tactic.

"This is another bargaining chip for negotiations to get the upper hand at the next round of six-way talks," South Korea's National Security Advisor Ra Jong-Yil told reporters here.

In Washington, US Secretary of State Colin Powell dismissed Pyongyang's latest outburst as nothing new as Bush headed to Asia for a week-long tour starting with talks in Tokyo with Japanese leader Junichiro Koizumi yesterday.

Japanese officials said leaders of the Asia-Pacific Economic Cooperation (Apec) forum, meeting Monday and Tuesday in Bangkok, will issue a statement calling for a crackdown on the spread of weapons of mass destruction and will consider issuing a separate and specific resolution on North Korea.

Foreign ministry spokesperson Hatsuhisa Takashima said that no "common consensus" had yet been reached on the second statement.

North Korea says it will never disarm while Washington maintains a "hostile" policy towards the communist state it dubbed a member of an "axis of evil" along with Iran and Iraq.

North Korea demands a legally binding non-aggression pact from the US as a first step before responding to Washington's demand for a complete and verifiable dismantling of its nuclear weapons drive.

Pyongyang attended six-way talks along with South Korea, China, Japan, Russia and the US in Beijing in August but later called them "useless" because Washington failed to agree to the pact.

Raising the stakes at the talks, North Korea threatened to test a weapon and declare itself a nuclear power, according to US officials.

In the ensuing weeks Pyongyang has claimed it is making atomic bombs after reprocessing spent fuel rods, and imposed further obstacles to a new round of talks by demanding that Japan be excluded.

In an apparent concession, Powell said last week that Washington was working on a security assurance involving multiple nations that he hoped would satisfy the isolated regime.

However, Pyongyang has indicated it is unlikely to be satisfied with anything less than a legally binding accord.

North Korea's latest announcement was seen as a slap in the face for a South Korean cabinet-level delegation in Pyongyang for the last four days.

The South Koreans, led by Unification Minister Jeong Se-Hyun, asked Pyongyang to return to the six-way talks and to refrain from escalating the crisis further.

However, the talks ended yesterday with no commitment from the North Koreans on multilateral talks. – Sapa-AFP.