Obama takes fight to North Korea on eve of summit

The warning came after Pyongyang raised the stakes in the ongoing standoff by threatening to hit "major targets" in Japan if Tokyo goes ahead with its threat to shoot down a North Korean missile. Japan has made no secret of its preparations to shoot down any part of the missile, including discarded boosters, which could threaten its territory.

The missile manoeuvres by North Korea are threatening to become the first major foreign policy crisis for President Obama. US defence officials warned yesterday that the North Korean military had begun fuelling the rocket as part of final preparations for the launch. The US and its allies in Nato, along with South Korea and Japan, argue that the aim is to test the rocket, a multi-stage Taepodong-2 that could potentially reach as far as Alaska, for military purposes. The regime in Pyongyang insists it intends only to put a satellite into orbit.

Behind the scenes at the G20 economic summit in London, American officials were lobbying other countries for support in referring North Korea to the UN Security Council for punishment in the event of a launch. Officials travelling with President Obama from London to Strasbourg for the two-day summit of the Nato military alliance that opens today acknowledged they had clear indications that a launch could be imminent. Fuelling usually comes four days before such a missile is fired.

US sources said that Washington was trying to apply direct pressure on Pyongyang to back off from the launch. "We have been making maximum efforts to try to dissuade them, and still hope that they may change their minds," one noted, adding that the Pentagon was also in direct contact with Japan, which would lie under the path of a long-range launch by North Korea.

Often belligerent in its rhetoric at times of heightened tension on the Korean peninsula, Pyongyang is not holding back this time either. "If Japan recklessly 'intercepts' the DPRK's [North Korea's] satellite for peaceful purposes, the Korean People's Army will mercilessly deal deadly blows not only at the already deployed intercepting means but at major targets," the regime said. It also threatened Japan with a "thunderbolt of fire" if it made any attempt at interception, and has served notice it would consider any attempt to bring the issue before the Security Council as an "act of war".

While the US can assume backing for UN action – possibly including new sanctions – from European governments, Japan and South Korea, bringing China and Russia on board may be harder. President Obama, on his first overseas trip this week, is having to combine responses to the global economic crisis, the war in Afghanistan (the development of which will dominate the Nato summit) and the escalating crisis posed by North Korea.

Even before the issue of the missile launch Washington was wrestling with how best to tackle the festering issue of North Korea's wider nuclear arms activities. The so-called six-party process to disarm the renegade state has at times seemed to make headway – most recently in June last year when the North Koreans blew up a cooling reactor at their Yongbyon nuclear plant, paid for by the Americans – only later apparently to go into reverse.

At their meeting Mr Obama and South Korea's Premier Lee Myung-bak agreed to keep up efforts to make verifiable progress on the ending of the North's nuclear capacity. The two men also promised to re-energise stalled negotiations on a free-trade treaty between South Korea and the US.

But the imminence of the missile firing topped the meeting, officials said. A statement issued by the South Korean delegation said the two men had agreed on the need "for a stern, united response from the international community" if it goes forward, clearly hinting they would seek UN sanctions.

In the stand-off with North Korea over its nuclear programme that has now lasted almost 16 years, China has always played a pivotal, if sometimes opaque, role. While for some years the nearest thing to an ally of the secretive regime, even Beijing in recent years has showed growing impatience with Pyongyang.

A senior Japanese official said his government would not be influenced by the warnings from Pyongyang and would consider any missile launch a violation of UN resolutions. Tokyo, he added, had been consulting with the US to "prepare for any eventuality".