"A meeting of delegations scheduled for December failed to take place ... It will be transferred to January, while the concrete date will depend on our success in the implementation of concrete commitments," Losyukov was quoted by the Itar-Tass news agency as saying.

Moscow "maintains optimism on talks on the nuclear problem of the Korean peninsula and hopes they will yield result," the diplomat said.

According to the deputy minister, there are some factors, preventing the solution of the problem of the final closure of nuclear facilities in the Democratic People's Republic of Korea (DPRK).

"Putting out of action the facilities is a difficult technical thing, and appraisals of experts differ on this point," he said. "Some say that this operation will take several months, while others -- around a year ... The process will continue; there is no need to make a tragedy out of this," Losyukov added.

"We should fulfill, above all, pledges on deliveries of petroproducts. But this question has not be resolved so far," he said. "There is an understanding at the government level, but it has not been implemented at the technical level."

At the same time, the deputy minister claimed that "the unsettled nature of these questions does not retard a solution of the general nuclear problem of the Korean Peninsula".

"We expect from the DPRK to open all its nuclear programs. However, the sides do not know when it happens." he said.

According to a six-party talks joint document released in Beijing on Oct. 3, the DPRK agreed to disable all its existing nuclear facilities and provide a complete and correct declaration of all its nuclear programs by the end of this year.

The document said the decommissioning of the five megawatt Experimental Reactor, the Reprocessing Plant (Radiochemical Laboratory) and the Nuclear Fuel Rod Fabrication Facility in Yongbyon would be completed by Dec. 31.