Russian President Vladimir Putin and South Korean President Moon Jae-in agreed on Friday to support "efforts to establish complete denuclearisation on the Korean peninsula" following the U.S.-North Korea summit last week.
A joint statement signed by the two leaders during a state visit by Moon to Russia was released by South Korea's presidential Blue House.
Moon said that co-operation with Russia was key to peace in the Korean Peninsula.
Speaking to parliament in Moscow, Moon thanked Russia for its efforts in bringing about a regional peace settlement.
Moon added that Pyongyang has taken real steps toward full denuclearisation.
President Vladimir Putin said Russia will continue to play its part in the search for a solution to the weapons standoff in the Korean Peninsula.
Moon arrived in Russia on Thursday, the first official visit by a South Korean president since 1999.
The Russian and South Korean leaders agreed that last week's historic summit in Singapore between U.S. President Donald Trump and North Korean leader Kim Jong Un would contribute to denuclearisation of the Korean peninsula.
Putin and Moon agreed to "continue joint efforts to establish complete denuclearisation on the Korean peninsula and secure permanent peace and stability on the peninsula and (in) Northeast Asia."
Moon said historic changes are happening in the Korean peninsula and steps are being taken towards denuclearisation.
Both Moscow and Seoul are hoping that reduced tensions with Pyongyang will open up opportunities for economic and infrastructure projects that would directly link South Korea with Russia through North Korea.
Those plans are currently blocked by international sanctions on North Korea which international leaders have said will not be lifted until North Korea makes significant moves to give up its nuclear weapons and ballistic missiles.
A number of countries, including South Korea and Russia, have nevertheless begun looking for ways to engage with North Korea economically should sanctions be lifted.
Putin and Moon agreed to joint research in the fields of electricity, gas and railways in order to advance cooperative projects between North Korea, Russia and South Korea.
Their statement said "large-scale infrastructure projects will contribute to Northeast Asia's peace and prosperity."
Railway projects were an area of common interest, the statement said, noting the development of a railway link between the Russian eastern border town of Khasan and the North Korean port of Rajin.
Putin and Moon also agreed to cooperate on joint research to connect the Trans-Siberian Railway and the Trans-Korean Railway.
In addition to security, Russia and South Korea talked about a free trade agreement
TRT World's Dan Ashby reports from Moscow.
Moon invited Putin to South Korea at a convenient time, which Putin accepted, the statement said.
South Korean President Moon Jae-in visited Moscow Friday on a trip intended to boost bilateral economic ties.
Following Moon's talks with Russian President Vladimir Putin in the Kremlin, officials from the two countries signed agreements on cooperation in various economic projects, energy, transport and innovative technologies.
Putin emphasized that South Korea is one of Russia's top partners in the region and voiced hope that their two-way trade will expand.
He hailed contacts between the two Koreas and the U.S.-North Korean summit.
"We hope that it would help significantly reduce tensions around the Korean Peninsula and create conditions for creating conditions for forming a stable security for all countries in the region," Putin said.
He vowed that Moscow also would try to help settle problems concerning North Korea.
Moon said Seoul was ready to promote a "strategic partnership" with Russia and paid homage to Russian culture, saying that he "fell in love with Russia after reading Tolstoy and Dostoyevsky."
He noted that Moscow and Seoul share a desire to further expand their ties.
The Kremlin has pushed for prospective trilateral economic projects involving Russia and both Koreas, including a railway link and a natural gas pipeline.
Future economic plans
Russian President Vladimir Putin on Friday invited his South Korean counterpart Moon Jae-in to an economic forum in Vladivostok in September, confirming his plans to host the leaders of both Koreas in Russia.
"We would be happy to see you as an honorary guest" at the Vladivostok forum which starts on September 11, Putin told Moon during a press conference after they held talks in Moscow.
The Russian leader has also invited North Korea's Kim Jong Un to the event, as well as the leaders of China and Japan.
So far, only Japan's Prime Minister Shinzo Abe has confirmed his attendance.
On Friday Russian media reported that Kim has not yet responded to the Kremlin's invitation.
"There has not been an answer yet," Putin's aide Yury Ushakov was quoted as saying by TASS news agency.
During his press conference with Moon, Putin said he "welcomed" a recent historic summit between Kim and US President Donald Trump in Singapore, when the two leaders signed a joint document calling for the denuclearisation of the Korean peninsula.
"We hope this will allow tensions to be significantly reduced in the Korean peninsula and in the future create conditions for the formation of a sustainable security system in the region," he said.
During his three-day visit, Moon is also expected to watch South Korea's World Cup match against Mexico on Saturday in the city of Rostov-on-Don.