What We Know About North Korea’s Role in the Ukraine War

Five months ago, the autocratic leaders of Russia and North Korea signed a treaty on mutual defense and cooperation, deepening ties between the two countries that stretch back beyond the Cold War.

Now, there are growing fears that North Korea’s leader, Kim Jong-un, will assist his Russian counterpart, Vladimir V. Putin, by sending soldiers to the battlefield in Ukraine. Mr. Putin launched the full-scale invasion of Ukraine more than two and half years ago, starting a war of attrition that has killed and wounded more than 600,000 Russian troops.

On Friday, South Korea’s intelligence agency said that Russian navy ships had begun transporting North Korean ​troops to the Russian Far East ​earlier this month. On Tuesday, President Volodymyr Zelensky of Ukraine said North Korea was preparing thousands of soldiers to fight on the Russian side.

Moscow and Pyongyang have denied the claims, and no hard evidence has emerged that North Korean troops have walked onto the battlefield yet.

North Korea has one of the world’s largest militaries, with 1.2 million soldiers, but it has not fought in a major conflict since the 1950-53 Korean War. For decades, Pyongyang claimed that its military buildup was for deterrence or war on the Korean Peninsula. Dispatching troops to the Ukrainian front would mark its first major intervention in a​n overseas war.

Here’s what to know about North Korea’s growing military ties with Russia.

Mr. Kim and Mr. Putin have met twice since last year, signing the treaty in Pyongyang in June. Mr. Putin has relied on Mr. Kim to replenish his dwindling weapons stockpiles.