Ukraine is calling on its allies to impose fresh sanctions on Pyongyang, and claims North Korea has sent thousands of troops to help Russia in its war effort.
President Volodymyr Zelensky has told Nato members and European leaders he had information that up to 10,000 North Korean specialists were being prepared to enter the war.
On a trip to Brussels, the Ukrainian leader said some North Korean specialists were already on the ground in parts of Ukraine's occupied territories.
It follows remarks the Ukrainian president made to his parliament, claiming intelligence services had confirmed North Korea's supply of both weapons and personnel to Russia.
Kim Jong Un with North Korean troops
REUTERS
Zelenskiy says he was briefed on North Korean 'involvement' in Ukraine war
REUTERS
He told lawmakers: "These are workers for Russian factories to replace Russians killed in the war. And personnel for the Russian army. In fact, this is the participation of a second state in the war against Ukraine on the side of Russia."
The Kremlin has branded the claims that North Korean troops are about to enter the war as "fake news".
North Korea is already known to have supplied large quantities of ammunition and missiles to Russia to help it prosecute its war against Ukraine.
Security sources report several thousand North Korean troops are currently training at military bases in Eastern Russia.
Intelligence analysts claim Russian President Vladimir Putin has been struggling to mobilise more Russian citizens to join the war effort.
LATEST DEVELOPMENTS:
Kim Jong Un greets North Korean troops
REUTERS
According to reports, September was the bloodiest month yet for Putin's troops in Ukraine.
Since the start of the war more than two-and-a-half years ago, at least 115,000 Russians have been killed and 500,000 wounded.
Any move to mobilise North Korean troops to enter the war in Ukraine would be fraught with difficulty.
Intigrating command structures, and the complexities around the different languages involved, are chief among the problems such a mobilised force would face.
Ukrainian Foreign Minister Andrii Sybiha said Kyiv's allies should respond firmly, including by imposing new sanctions and further isolating Pyongyang, whose relations with Russia have grown closer since Moscow's invasion of Ukraine in February 2022.
Russian tank firing shells in Ukraine war
REUTERS/CCTV
"This is a huge threat of further escalation. We are approaching a new phase, new realities of war," he said at a news conference in the Black Sea city of Odesa.
President Zelensky is raising those concerns with Nato and European leaders in Brussels today, as he presents the Alliance with Ukraine's "victory plan".
The Ukrainian leader is once again pressing for a Nato membership invitation and a major increase in military support for Kyiv's defence.
Zelensky's plan contains requests that Ukraine's allies have so far declined to grant.
As well as a renewed call to be allowed to join Nato, he wants approval to use Western missile systems to strike deep inside Russia.
The Ukrainian president said, if adopted, his plan could end the war "no later than next year".