Vladimir Putin and Kim Jong Un discussed the possibility of sending a North Korean into space, Russian news agencies quoted Putin's spokesman as saying.

President Putin and the North Korean leader held talks on Wednesday at a spaceport in Russia's far east.

"We talked about the fact that if the North Korean side wishes, a North Korean cosmonaut can be trained and sent into space," the TASS and RIA Novosti news agencies quoted Dmitry Peskov as saying.

If that were to happen, the cosmonaut would be the first North Korean ever to go into space.

Kim is visiting Russia as Putin seeks to bolster alliances with other leaders ostracised by Western countries.

The two leaders met at the Vostochny Cosmodrome, with footage released by the Kremlin showing the pair shaking hands enthusiastically as Kim arrived.

They then toured assembly and launch facilities for the Angara and Soyuz-2 space rocket launchers before sitting down for talks.

Kim "shows great interest in rocket technology, and they are trying to develop (their presence in) space", Putin said.

The meeting at the cosmodrome was symbolic, especially as Pyongyang recently failed twice in its bid to put a military spy satellite into orbit.

In April 2008, Yi So-Yeon became the first Korean sent into space. The South Korean flew on a Russian Soyuz spacecraft to conduct a mission on the International Space Station.

At the time, Yi said she hoped her journey would inspire South Korea to greater space endeavours and even help bring reconciliation on the divided peninsula.

Putin accepts Kim's invitation to visit North Korea   

During Wednesday's talks Putin accepted an invitation to visit North Korea, Pyongyang's state media said Thursday.

Kim "courteously invited Putin to visit the DPRK at a convenient time", state-run KCNA said, referring to the country by its official name.

"Putin accepted the invitation with pleasure and reaffirmed his will to invariably carry forward the history and tradition of the Russia-DPRK friendship."

North Korea's leader Kim Jong Un (L) shaking hands with Russia's President Vladimir Putin.

Kim told Putin on Wednesday he was sure Russia would win a "great victory" over its enemies.

"We will always be with Russia," Kim said, according to footage broadcast on Russian TV. 

"An old friend is better than two new ones," Putin said, quoting a Russian proverb and referencing the Soviet Union's role in the Korean War.

Kim then "said goodbye to Putin, wishing him good health" and headed to his next destination, KCNA said, with Putin earlier saying Kim would oversee a display of Russian warships in the far eastern city of Vladivostok to "demonstrate the capabilities of the Pacific Fleet".

- 'Blood alliance' -

Western countries have repeatedly raised concerns of a possible arms agreement between Russia and North Korea, as Moscow's war in Ukraine grinds on.

"The summit signals a seismic change in the Northeast Asian geopolitics," said Kim Jong-dae, a former MP and visiting scholar at Yonsei Institute for North Korean Studies.

A stronger alliance between North Korea, Russia and China could become a "destabilising force in the region", and ammunition from Pyongyang could significantly impact the war in Ukraine.

"I think Russia has already tested the North Korean shells in battlefields and is now ready to expand its use going forward. And neither the US nor South Korea has come to grips with the implications of such an arms deal between Russia and the North," he said.

Russia became a pariah in the West after invading Ukraine last year and has looked to strengthen alliances with other leaders facing similar isolation.

Putin on Wednesday praised the "strengthening of cooperation and friendship between our countries", while hosting Kim at a spaceport in Russia's far east.

He also said Moscow could help Pyongyang build satellites -- after the North failed twice recently to put a military spy satellite into orbit.

In Washington, State Department spokesman Matthew Miller said any cooperation would be "quite troubling and would potentially be in violation of multiple UN Security Council resolutions".

Kim, who travelled overland to Russia in his bullet-proof train, was accompanied by a military-heavy entourage, with top Russian military officials including Defence Minister Sergei Shoigu also involved in the talks.

"With Kim Jong Un's latest visit to Russia, North Korea-Russia relations can be said to have completely returned to the level of blood alliance during the Cold War," Cheong Seong-chang, researcher at the Sejong Institute, told AFP.

"There have been many summit meetings between North Korea and Russia so far, but there has never been a time when North Korea brought in almost all of its key military officials like the one happening right now."