South Korean intelligence has found that North Korea has dispatched 12,000 troops to support Russia’s war with Ukraine, Yonhap news agency in South Korea reported on Friday.

Yonhap cited the National Intelligence Service (NIS) that the North Korean troops have already left the country.

The NIS did not immediately confirm the report.

But South Korea’s presidential office said in a statement that President Yoon Suk Yeol had presided over an emergency meeting earlier on Friday to discuss North Korea’s troop dispatch to Ukraine.

The statement said participants of the meeting agreed that North Korea’s troop dispatch poses a grave security threat to South Korea and the international community.

Nato secretary-general Mark Rutte, left, with Ukraine’s President Volodymyr Zelensky during the Nato-Ukraine Council working dinner at Nato headquarters in Brussels on Thursday (Olivier Matthys, Pool Photo via AP)

But the presidential office gave no further details such as when and how many North Korean soldiers have been sent to Ukraine and what roles they are expected to play.

The office’s public affairs office did not immediately confirm whether South Korea has officially verified the North Korean troop deployment.

Ukrainian media reported earlier this month that six North Koreans were among those killed after a Ukrainian missile strike in the partially occupied eastern Donetsk region on October 3.

On Thursday, Ukrainian President Volodymyr Zelensky said his government has intelligence that 10,000 troops from North Korea are being prepared to join Russian forces fighting against his country, warning that a third nation wading into the hostilities could turn the conflict into a “world war”.

“From our intelligence we’ve got information that North Korea sent tactical personnel and officers to Ukraine,” Mr Zelensky told reporters at Nato headquarters.

“They are preparing on their land 10,000 soldiers, but they didn’t move them already to Ukraine or to Russia.”

Nato secretary-general Mark Rutte said the western alliance “have no evidence that North Korean soldiers are involved in the fight. But we do know that North Korea is supporting Russia in many ways, weapons supplies, technological supplies, innovation, to support them in the war effort. And that is highly worrying.”

The US, South Korea and their partners have accused North Korea of supplying Russia with artillery shells, missiles and other equipment to help fuel its war in Ukraine.

Outside officials and experts say North Korea in exchange possibly received badly needed food and economic aid and technology assistance aimed at upgrading President Kim Jong Un’s nuclear-armed military.

Both Moscow and Pyongyang have repeatedly denied the existence of an arms deal between the countries.