SEOUL, Oct. 28 (UPI) -- Russia has begun sending North Korean troops to a frontline area in unmarked civilian trucks, Kyiv's military intelligence said, as concerns mount over Pyongyang's involvement in Moscow's war against Ukraine.
Russian police stopped a truck with civilian license plates carrying North Korean soldiers, the Defense Intelligence of Ukraine said Sunday, citing intercepted audio.
"The driver, who was driving reinforcements from the DPRK in a trailer, did not have a combat order," the report said, using the official acronym for North Korea. The truck was later permitted to continue along a highway that runs from Voronezh to the southwestern region of Kursk, where Ukrainian forces have occupied hundreds of square miles since August.
Ukrainian President Volodymyr Zelensky said Sunday that North Korean troops may join the battle against Ukraine "in a matter of days."
"Ukraine could soon be forced to fight North Korean troops in Europe," Zelensky said in a post on X.
Last week, Seoul and Washington confirmed that the North has dispatched at least 3,000 soldiers to eastern Russia this month, where they are being trained.
U.S. National Security Council spokesman John Kirby said Thursday that the deployment of North Korean troops was "highly concerning," adding that they would be "fair game" on the battlefield.
Seoul's National Intelligence Service said last week that the North plans to send around 10,000 troops by December. Pyongyang has already supplied more than 13,000 containers of artillery, missiles, anti-tank rockets and other deadly weapons to Russia on more than 70 occasions since August last year, the NIS said.
Russia and North Korea have drawn closer since Moscow's invasion of Ukraine in February 2022, with the two regimes signing a mutual defense pact in June.
Neither Moscow nor Pyongyang have given clear answers about the deployment of North Korean troops. On Friday, the North's Foreign Ministry said that it "does not feel the need to confirm" the reports of troops being dispatched, but argued such a move would not violate international law.
"If there is such a thing that the world media is talking about, I think it will be an act conforming with the regulations of international law," Vice Foreign Ministry Kim Jong Gyu said in a statement carried by the official Korean Central News Agency.
Russian President Vladimir Putin also gave a non-denial answer when asked last week about satellite images of North Korean troops in Russia.
"Images are a serious thing," Putin said during a press conference at the BRICS summit in Kazan, Russia, on Thursday. "If there are images, then they reflect something."
South Korea has provided humanitarian and financial aid to Ukraine but has so far refrained from directly supplying weapons. President Yoon Suk Yeol said last week, however, that Seoul would not "sit idle" in response to the North's deployment of troops.
"If North Korea dispatches special forces to the Ukraine war, we will provide support to Ukraine step by step and consider taking necessary measures for the security of the Korean Peninsula," Yoon said at a joint press conference with Polish President Andrzej Duda in Seoul.
"We have adhered to a principle of not directly supplying lethal weapons, but we can review this more flexibly depending on North Korean military activities," Yoon said.