North Korean troops have been sent to Russia, U.S. confirms

North Korea has sent troops to Russia, the United States said Wednesday, its first public confirmation of a move that has rattled Western allies and could mark a major escalation of Moscow's war in Ukraine.

"There is evidence of DPRK troops in Russia," Defense Secretary Lloyd Austin told reporters in Rome, using the abbreviation for North Korea's formal name, the Democratic People's Republic of Korea.

"What exactly they're doing is left to be seen," Austin said, adding, "We're trying to gain better fidelity on it." It's a "serious issue," he said, if North Korea's "intention is to participate in this war on Russia's behalf."

His comments came after South Korea and Ukraine sounded the alarm in recent days, sharing intelligence and voicing dissatisfaction with what they see as a lack of urgency in the response from the U.S. and other Western countries.

The reclusive nature of the Kremlin and Kim Jong Un's regime mean that observers have pored over social media video and satellite images in search of confirmation that Russia is deploying the troops to Ukraine, in what would be a dramatic new step in the burgeoning alliance between Pyongyang and Moscow. 

South Korean lawmakers said Wednesday that North Korea had sent 3,000 troops to Russia out of a promised 10,000 to be deployed by December. That is twice the 1,500 that the South Korean intelligence agency had reported being sent last week.

On Tuesday, Ukrainian President Volodymyr Zelenskyy said that two units of North Korean troops, with as many as 6,000 people each, were being trained for deployment.

"This is a challenge, but we know how to respond to this challenge. It is important that partners do not hide from this challenge as well," he said in his nightly video address.

Lt. Gen. Kyrylo Budanov, the head of Ukraine's Main Directorate of Intelligence, told the U.S. publication The War Zone that North Korean troops could arrive as early as Wednesday in Russia's Kursk region, where Ukrainian forces launched an incursion in August.

South Korea summoned the Russian ambassador on Monday to demand the withdrawal of the North Korean soldiers and "related cooperation." The U.S. treaty ally, which has so far provided only nonlethal aid to Ukraine, now says it is considering providing defensive weapons and even offensive ones in response.

State Department deputy spokesperson Vedant Patel said Tuesday that it would "mark a dangerous and highly concerning development" and that the U.S. was consulting with its allies and partners "on the implications of such a dramatic move."

Austin had not mentioned the reports during his Monday visit to Kyiv, where he met with Zelenskyy and announced $400 million in new military aid.

The U.S. and others say Pyongyang is already supplying Moscow with badly needed munitions, including millions of artillery shells, in exchange for key military technology that could be used to strengthen Kim's nuclear and ballistic missile programs. Both Russia and North Korea deny any transfer of arms.

In addition to giving Russia a boost on the battlefield, the involvement of North Korean troops would solidify the growing ties between Russian President Vladimir Putin and Kim, who signed a pact in June that includes a pledge of mutual defense. 

"The Russians are going to appreciate some of the backfilling and assistance," said Frank Ledwidge, a former British military intelligence officer and senior lecturer in war studies at England's University of Portsmouth. 

"It will help them in securing and reinforcing their lines of supply for artillery mainly because North Korea is an artillery power," he told NBC News.

Ledwidge and others say it could also provide the large but little-tested North Korean military with critical combat experience and real-time information about the performance of its weapons systems as Kim ramps up his war rhetoric against Washington and Seoul.

The reports of North Korean soldiers fighting for Russia have also revived discussion on whether countries in Europe should send their own troops to support Ukraine.

"Everyone flips out whenever they talk about European troops going to Ukraine, that it's far too escalatory. And then the Russians just go ahead and bring in outside troops," said Phillips O'Brien, a professor of strategic studies at the University of St. Andrews in Scotland. 

"The escalation has already happened."

The South Korean intelligence service said last week that North Korea had sent about 1,500 special forces soldiers for training in neighboring Russia on vessels from Russia's Pacific Fleet. Upon arrival, the agency said, they received Russian military uniforms and Russian-made weapons as well as fake identification documents to make it look as if they come from Russia's Far East, where people can resemble North Koreans. 

The agency told NBC News on Wednesday that it had used AI facial-recognition technology to confirm that a North Korean soldier seen in a photo taken in Ukraine is Ri Song Jin, who also appeared with Kim last year in photos from a visit to a North Korean weapons factory. 

The agency said the photo showed Ri sitting with a Russian soldier at the launch site for a North Korean missile in Ukraine's Donetsk region. 

The North Korean missile technicians deployed to frontline areas in Ukraine "are there to provide support in using the North Korean missiles, to find out technical problems and also to secure additional technologies," the agency said.

The agency also released satellite images from last week of a training ground in Russia's Far East that it said showed hundreds of North Korean soldiers gathering at military facilities.

North Korea's envoy to the U.N. dismissed the accusations as "groundless rumors" on Monday. The Kremlin says its cooperation with North Korea is not directed against anyone else. 

Spokesperson Dmitry Peskov did not directly answer questions about whether North Korean troops were fighting for Russia, saying there was "conflicting information."

"South Korea says one thing, then the Pentagon says they have no confirmation of such statements," he told reporters on Monday, before Austin's comments.

Others have also questioned the reports of North Koreans in Ukraine, with Andriy Kovalenko, the head of Ukraine's Center for Countering Disinformation, warning that Russia could be using them for propaganda purposes.

"There are no North Korean soldiers, yet," his office said.

North Korea has the world's fourth-largest military with around 1.2 million military personnel, according to the Council on Foreign Relations, a New York-based think tank. The deployment in Ukraine, if confirmed, would mark the North Korean military's first direct involvement in a conflict since the 1950-53 Korean War.

Still, their addition would be "incremental," Ledwidge said, with a few thousand troops unlikely to make much difference at all, let alone win the war for Russia. 

It's more of a political statement to signal the deepening alliance between Moscow and Pyongyang, he said, and would provide a training ground for inexperienced North Korean soldiers, adding to Seoul's worries.

"North Korea gets to bring back home some combat experience," he said.

The language barrier between Korean-speaking and Russian-speaking soldiers would be another obstacle.

"They're not going to break up the Koreans and stuff them into Russian units," O'Brien said. "It would be a disaster." 

"What we'll see is Korean units acting together as Korean formations. The Korean ones will be in liaison with the Russians, and they will get their orders back and forth," he said.  

The first troops could likely be a "trial run," he said. "And if it works, well, my guess is they'll be back."