G8 foreign ministers have condemned in the "strongest possible terms" North Korea's nuclear weapons and ballistic missile programmes.

The group, meeting in London, warned the regime it faced fresh sanctions if it goes ahead with a predicted missile test in the escalating nuclear stand-off with its neighbours and their Western allies.

Foreign Secretary William Hague said they had committed themselves to "further significant measures" if the test went ahead.

"Clearly what we are talking about is in the field of sanctions. We would discuss such measures at the UN Security Council," Mr Hague said.

In a communique, G8 ministers also said the regime's "aggressive rhetoric" would only serve to deepen the country's isolation and urged it to join "credible and authentic multilateral talks" on denuclearisation.

North Korea said "powerful striking means" had been put on standby for a missile launch "and the co-ordinates of targets put into the warheads".

Few analysts believe the regime's untried young dictator Kim Jong Un wants war, despite the blood-curdling threats of recent weeks, but there are fears a miscalculation could lead to dangerous escalation in the region.

Officials in Washington and Seoul have said the nuclear-armed regime appears to be preparing to test fire a medium-range Musudan missile, thought to be capable of reaching Japan and the US territory of Guam in the Pacific.

Mr Hague said G8 ministers – from the US, UK, Russia, France, Germany, Japan, Italy and Canada – did not want to exacerbate tensions in the region where foreign diplomats have been warned the north cannot protect them during a war.