North Korea may supply Russia with more weaponry for its war in Ukraine and other military cooperation, it has emerged.

Kim Jong-un plans to travel to Russia this month to hold a 'leader-level diplomatic engagement' with Vladimir Putin, the New York Times reported on Monday, citing US and allied sources.

Officials say Kim - who rarely travels outside his country - is likely to travel this month to Vladivostok, on Russia's Pacific coast not far from North Korea, to meet with Putin. 

Moscow has also taken steps to strengthen its military ties with North Korea with Russian Defense Minister Sergei Shoigu claiming on Monday that the two countries may hold joint war games. 

It comes after Shoigu travelled to Pyongyang last month in a bid to convince North Korea to sell artillery ammunition to the Kremlin. 

Last week the White House said that Russia was already in secret, active talks with the North to acquire a range of munitions and supplies for Moscow's fight in Ukraine. 

The US has reason to think Kim 'expects these discussions to continue' and 'to include leader-level diplomatic engagement in Russia', National Security Council (NSC) spokeswoman Adrienne Watson said said on Monday. 

'As we have warned publicly, arms negotiations between Russia and the DPRK are actively advancing,' she said, using an acronym for the North.

'We have information that Kim Jong Un expects these discussions to continue, to include leader-level diplomatic engagement in Russia.'

Watson said Monday that the United States urged North Korea 'to cease its arms negotiations with Russia and abide by the public commitments that Pyongyang has made to not provide or sell arms to Russia.'