Russia on Saturday called for "maximum responsibility and restraint," after North Korea declared it was in a "state of war" with South Korea and warned Seoul and Washington against any provocation.
"We expect all sides to show maximum responsibility and restraint and that no-one will cross the line after which there will be no return," Grigory Logvinov, a Russian foreign ministry pointman on North Korea, told the Interfax news agency.
"Naturally, we cannot remain indifferent when an escalation of tensions is taking place at our eastern frontiers," the Russian diplomat was quoted as saying. "We cannot but worry."
Logvinov said Russia was in "constant touch" with its partners involved in six-party nuclear negotiations, wich include the two Koreas, China, the US, and Japan.
Separately, the Interfax news agency quoted a diplomatic source as praising South Korea and the United States' positions in the stand-off with North Korea.
"The situation is, of course, very tense and dangerous but still there are some encouraging moments: the reaction from the United States and South Korea is measured and calm to a certain degree," the source was quoted as saying.
"It is not the time to breathe fire," the source added. "The time has come for active, non-public diplomacy aimed at searching for a political settlement within the framework of international law including the decisions of the UN Security Council which are binding in nature."
North Korea on Saturday declared it was in a "state of war" with South Korea and warned Seoul and Washington that any provocation would swiftly escalate into an all-out nuclear conflict.
The United States said it took the announcement "seriously", but noted it followed a familiar pattern, while South Korea largely dismissed it as an old threat dressed in new clothing.