Russia has reportedly gathered around 50,000 soldiers, including North Korean forces, in preparation for an offensive aimed at retaking territory captured by elite Ukrainian forces in Russia’s Kursk region, according to American and Ukrainian officials cited by The New York Times.

A new U.S. assessment reveals that Russia has built up these forces without redeploying soldiers from eastern Ukraine, which remains Moscow’s main focus, allowing Russia to exert pressure across multiple fronts simultaneously.

The primary objective of Russian forces is to reclaim land in Kursk that Ukraine occupied earlier this year. Thus far, Russian troops have used missile strikes and artillery against Ukrainian positions in Kursk but have not launched a large-scale ground attack, U.S. officials said.

Ukrainian officials anticipate an imminent assault, potentially involving North Korean soldiers who are reportedly training with Russian troops in the western area of Kursk.

This joint Russian-North Korean offensive is emerging as President-elect Donald Trump prepares to assume office, having pledged a swift resolution to the war. However, Trump has yet to outline his strategy, while Vice President-elect J.D. Vance has proposed a plan allowing Russia to retain captured Ukrainian territories.

Some U.S. military and intelligence officials have grown more pessimistic about Ukraine’s prospects, observing that Russia continues to seize ground both in Kursk and eastern Ukraine. According to these officials, part of Ukraine’s difficulty stems from challenges in maintaining adequate troop levels.

President Joe Biden has championed support for Ukraine, encouraging Congress to authorize billions in aid and instructing U.S. military and intelligence agencies to provide Kyiv with critical information to aid in its defense efforts.

One Western official pointed out that Ukraine’s unexpected incursion into Kursk in August weakened its forces in eastern Ukraine, exposing them to potential Russian advances. However, U.S. and Ukrainian officials believe that Ukraine has established strong defenses in Kursk, potentially allowing it to withstand attacks for some time.

Western and Ukrainian officials view the arrival of North Korean troops as a significant escalation after more than two years of conflict. North Korea has reportedly deployed over 10,000 soldiers for combat operations in Kursk, U.S. officials say.

North Korean troops, outfitted in Russian uniforms and equipped by Moscow, are expected to operate in separate units, U.S. defense officials confirmed. Ukrainian officials also reported that Russia has supplied North Korean forces with machine guns, sniper rifles, anti-tank missiles, and rocket-propelled grenades.

North Korea’s large military has been absent from ground combat for decades, but the troops now deployed are from its elite 11th Corps, a specialized operations unit known for its combat skills.

Ukrainian forces have gained hundreds of square kilometers with minimal resistance, though Russia has since reclaimed about half of the lost land and now appears prepared for a larger-scale operation.

U.S. officials predict that Ukrainian forces will be challenging to displace and that Russian and North Korean troops are likely to face significant casualties, similar to Russia’s losses in eastern Ukraine.

In exchange for deploying its soldiers, North Korea is believed to expect missile and rocket technology, as well as diplomatic support, from Russia. Ukrainian officials also speculate that North Korea is using this opportunity to harden its forces through combat experience.

U.S. defense officials have not confirmed whether North Korea plans to send additional reinforcements, though a senior Ukrainian intelligence official has suggested that North Korea might deploy as many as 100,000 troops.

Facing increasing losses, Russia struggles to meet its monthly recruitment target of around 25,000 soldiers, making North Korean troops crucial. Analyst Baros described North Korea’s military support as an “alternative supply line.”

“This is unlikely to be a one-off deployment of 10,000 troops. More likely, it’s a system to draw thousands—perhaps up to 15,000 soldiers per month—on an ongoing basis,” he said.