North Korea's relations with Russia have reached a new high point and President Vladimir Putin's visit to Pyongyang will further strengthen ties, North Korean leader Kim Jong Un said Wednesday.

Putin landed in North Korea earlier, in a trip set to boost defence cooperation between the two nuclear-armed countries as Moscow pursues its offensive in Ukraine.

"Relations between our countries are entering a new era of blossoming, which cannot be compared even with the period of Korean-Soviet relations of the last century," Kim said during talks with Putin in Pyongyang, according to Russia's RIA Novosti news agency.

During Putin's visit "the ardent friendship of the two countries will be strengthened," Kim said.

Moscow and Pyongyang's close ties have sparked anxiety in the West, which believes Russia has been procuring and using North Korean weaponry to wage its military offensive in Ukraine.

The two countries have been allies since North Korea's founding after World War II and have drawn even closer as Russia seeks to forge a united front against the West.