The Korean crisis will be high on the agenda when foreign ministers from the G8 group of nations hold talks in London on Thursday.

BBC correspondents say Japan, present at the talks, is looking for a strong statement of solidarity over the issue.

North Korea has been making bellicose threats against South Korea, Japan and US bases in the region.

Ministers will also debate the Syrian crisis, Iran's nuclear program and sexual violence in conflicts.

The BBC's diplomatic correspondent James Robbins says ministers agree that the combination of warlike threats from Pyongyang and preparations for new missile tests amount to dangerous provocation.

"There is no disagreement with the United States over North Korea," Russian Foreign Minister Sergei Lavrov said at a meeting with US Secretary of State John Kerry in London on Wednesday.

South Korea has raised its alert level amid indications that the North is preparing for a missile test.

Pyongyang has increased its fiery rhetoric following fresh UN sanctions imposed after its third nuclear test and joint military manoeuvres by the US and South Korea.