The move "cannot but evoke disappointment and concern among us," the ministry said in a statement. "We call on North Korea to continue disabling the Yongbyon nuclear objects and complete this process by the end of October."

Pyongyang said Tuesday that it had stopped disabling its nuclear plants at the Yongbyon complex as of August 14 and wanted to resurrect them because the United States had failed to remove it from a terrorism blacklist.

Washington condemned the decision and accused North Korea of violating a six-nation accord aimed at restraining its nuclear weapons program.

"Essentially what is happening is that the process of the denuclearisation of the Korean peninsula has again been interrupted by an extremely undesirable pause and, unfortunately, the possibility of its reversal has arisen," the Russian foreign ministry said.

Russia is one of six countries participating in the talks, which led to a deal last year under which North Korea agreed to shut down the Yongbyon complex, its main nuclear facility.