Kim's rare trip out of his isolated country -- his first official visit abroad since the Covid-19 pandemic began -- has fanned fears among Western countries that Moscow and Pyongyang will strike an arms deal in defiance of sanctions.

Moscow is believed to be interested in buying North Korean ammunition to continue fighting in Ukraine, while Pyongyang wants Russia's help to develop its missile programme.

The Kremlin has said no agreement has or will be inked.

But Kim's extended tour of Russia's far eastern region, which began Tuesday, has leaned heavily martial, including his military-dominated entourage, symbolic exchange of rifles with President Vladimir Putin and tour of a fighter jet factory in engineering hub Komsomolsk-on-Amur.

After meeting Kim on Wednesday at the Vostochny cosmodrome roughly 8,000 kilometres (5,000 miles) from Moscow, Putin talked up the prospect of greater cooperation with North Korea and said there were "possibilities" for military ties.

He also told Russian television that Kim's visit would include a stop a the port of Vladivostok to oversee a display of Russian warships.

Upon arriving in the large coastal city close to the Chinese and Russian borders, Kim was greeted by Shoigu and an honour guard, TASS reported.

In addition to observing Russia's Pacific Fleet, Kim is expected to visit the Far Eastern Federal University and marine biology laboratories at the Russian Academy of Sciences, according to the itinerary Putin described.

Colleges in Russia's Far East have historically accepted North Korean students.

- 'Troubling' cooperation -

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

The longtime allies are both under a raft of international sanctions, Moscow for the Ukraine conflict and Pyongyang for its nuclear tests.

Kim and Putin's gifting each other rifles at the spaceport summit on Wednesday further fuelled speculation that an arms export deal could be on the table, despite Western warnings.

Kremlin spokesman Dmitry Peskov told reporters on Friday however, that no agreements had been signed during Kim's ongoing trip, and "there was no plan to sign any".

While meeting Kim, Putin accepted an invitation to visit North Korea, according to the Kremlin, and he reportedly offered to send a North Korean to space, which would be a first.

Moscow also mentioned the possibility of helping North Korea to manufacture satellites, a prospect that has alarmed Washington.

The cooperation announced during Kim's Russia is "quite troubling and would potentially be in violation of multiple UN Security Council resolutions", State Department spokesman Matthew Miller told reports following the leaders' summit.

North Korean satellites, he noted, have been used to develop Pyongyang's ballistic missiles.

Pyongyang recently failed twice in its bid to put a military spy satellite into orbit.