North Korea will put two US journalists arrested last month on its border with China on trial to face criminal charges, further ratcheting up tensions since its rocket launch on April 5.

The announcement comes as Russia's foreign minister wrapped up a visit to the North's capital, trying to press Pyongyang not to restart its nuclear arms programme.

"A competent organ of the DPRK (North Korea) concluded the investigation into the journalists of the US. The organ formally decided to refer them to a trial on the basis of the confirmed crimes committed by them," the North's KCNA news agency said in a brief dispatch.

The pair, Euna Lee and Laura Ling of US media outlet Current TV, were arrested in March along the border between North Korea and China. North Korea has accused them of illegally entering its territory with "hostile" intent.

The US State Department had no immediate comment and the US embassy in Seoul also declined to comment.

The planned trial comes as the reclusive state faces UN Security Council censure for launching a long-range rocket on April 5 that regional powers say was a ballistic missile test in disguise.

Russian Foreign Minister Sergei Lavrov said while visiting the North's capital last week there was no easy solution to the international crisis surrounding the North's missile and nuclear arms programme.

He also told the North Koreans that all sides in the nuclear talks among the two Koreas, China, Japan, Russia and the US should look for ways to resume the often-stalled discussions, a Russian diplomat quoted him as saying.

The North's state news agency said the Russian delegation "reconfirmed its previous stand of opposing UN sanctions on the DPRK and paid attention to our stand that six-party talks have become no longer useful".