"Right now a lot of statements are appearing that some preparations are underway for new tests or the resumption or ramping up of activity in the nuclear and rocket spheres," said Russian Foreign Minister Sergei Lavrov.
"First of all, it is best to put forward such statements when they are based on facts -- not through the media," Lavrov told reporters after talks with a special envoy of North Korean leader Kim Jong-Un.
"This is why we propose that the activities of a working group on peace and security on the Korean peninsula be resumed," Lavrov said after talks with Choe Ryong-Hae.
"We are hoping that our partners will support our proposals to resume the work of the group."
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Choe did not address the media.
Russia, the United States, China, South Korea and Japan have for years sought to persuade North Korea to abandon its nuclear programme in exchange for aid and security guarantees.
The negotiations known as six-party talks began in 2003 but have been long dormant.
New satellite imagery shows steam rising from a re-processing plant at the North's main Yongbyon nuclear complex -- a sign consistent with maintenance and testing prior to commencing operations, the US-Korea Institute at Johns Hopkins University said on its closely followed 38 North website.
Lavrov slammed as "counter-productive" the UN resolution that lays the groundwork for putting the Stalinist regime in the dock for crimes against humanity.
Choe, who is on a week-long visit to Russia, was received by President Vladimir Putin at the Kremlin on Tuesday.