North Korea enters Ukraine fight for first time, officials say

North Korean troops have entered the fight in Russia's war against Ukraine, clashing for the first time with Ukrainian forces who are occupying a large chunk of Russia's Kursk region, according to a senior Ukrainian official and a senior US official.

The engagement was limited, the Ukrainian official said, and likely meant to probe the Ukrainian lines for weaknesses. The North Koreans fought together with Russia's 810 Separate Naval Infantry Brigade, the official said.

It was unclear when the fighting took place. The Ukrainian official offered no details about casualties, but the US official said a significant number of North Korean troops were killed. Both officials spoke on the condition of anonymity to share sensitive military information.

The North Korean troops are part of what Ukrainian and Western officials estimate to be a contingent of about 10,000 soldiers sent by the North's leader, Kim Jong Un, to bolster Russian forces trying to dislodge the Ukrainians from the Kursk region. Ukraine's forces hold about 250 square miles there after an incursion that began last summer.

Though the bulk of the North Korean troops have not yet seen action, Western and Ukrainian officials have called their appearance on the battlefield a major escalation after more than two years of war.

In his nightly address, President Volodymyr Zelenskyy of Ukraine seemed to confirm that North Korean forces had entered the fight, and he called on Ukraine's allies to assist in confronting this new threat.

"The first battles with North Korean soldiers mark a new chapter of global instability," he said. "Together with the world, we must do everything to ensure that this Russian step toward expanding the war -- this true escalation -- becomes a loss."

The North Korean soldiers began arriving by boat in the far eastern Russian port city of Vladivostok last month, then embarked on a 4,000-mile journey west to the Kursk region.

Much of the rest of the force could enter the fight in the coming days, the senior Ukrainian official said. The North Korean troops, the official said, have been divided into two units -- one made up of assault troops and another of support troops who will organize the defense of territory recaptured from Ukrainian forces.

There has been debate in Ukraine and among its allies about the military significance of the North Korean troops. Some officials have described their recruitment as an act of desperation by Russia's president, Vladimir Putin, whose forces continue to take territory in eastern Ukraine but at huge losses.

Others have said the decision to deploy the troops was meant to weaken Western resolve by showing that Russia remains far from isolated. The North Korean troops could also allow Russia to divert more of its forces to offensive operations on Ukrainian territory, in particular in the Donbas, where Russian troops are attempting to take as much territory as possible before the harsh winter sets in.

It is not clear what Putin promised Kim, if anything, in exchange for the troops. For now, US officials say they have seen no evidence of a quid pro quo. But there are concerns that Russia might provide some kind of significant military assistance that could enhance the danger North Korea poses to its neighbors and the United States.

Last week, North Korea launched an intercontinental ballistic missile in the direction of Japan, setting off a new flurry of anxiety in the West.

In addition to its troops, North Korea has provided Russia 16,000 shipping containers full of artillery shells, rockets and missiles since the summer of 2023, according to US and South Korean officials. In June, Putin met with Kim in Pyongyang, where they restored a Cold War-era treaty of mutual defense and military cooperation between their countries.