FILE PHOTO: Ukrainian servicemen ride a military vehicle in the Sumy region, near the Russian border on August 10, 2024.
CNN  — 

Ukrainian President Volodymyr Zelensky said Monday that Russia has deployed nearly 50,000 troops to Kursk, the southern Russian region where Kyiv launched its surprise counteroffensive in the summer.

Ukrainian troops “continue to hold back” the “nearly 50,000-strong enemy group” in Kursk, Zelensky said in a post on Telegram after receiving a briefing from General Oleksandr Syrskyi, the Commander-in-Chief of Ukraine’s Armed Forces.

Russian forces launched offensives into Kursk in several waves on Monday, a spokesperson for one of Ukraine’s mechanized brigades said Tuesday, though none of them were successful.

“They stormed with a battalion-sized force,” Anastasiia Blyshchyk said, adding that Ukrainian forces destroyed Russian vehicles and equipment, and that “the Russian invaders were eliminated.” It was “a black day for the Russian occupiers,” she said.

Kyiv launched its incursion into Russia’s Kursk region in August, taking by surprise not just Moscow, but also its allies. It said at the time that the operation was necessary, because Russia had been planning to launch a new attack on Ukraine from the region. It said it was aiming to create a “buffer zone” to prevent future cross-border attacks.

The Kursk offensive, the first ground invasion of Russia by a foreign power since World War II, caught Moscow completely unprepared.

Ukrainian troops advanced quickly, deep into Russia’s territory and have since maintained control over hundreds of square miles of Russia’s territory. And while Russia has reclaimed some settlements, the line of control has barely changed over the past months.

A US official told CNN on Sunday that Russia has amassed a large force of tens of thousands — including recently arrived North Korean troops — to carry out an assault on the Ukrainian positions in Kursk. The official said the offensive was expected in the coming days.

The Kremlin has not commented on the presence of North Korean troops on its territory. At a meeting of the UN Security Council last week, Russia refused to answer questions from the US about its deployment of North Korean troops.

At the same time though, Russian state media TASS reported Saturday that Russian President Vladimir Putin signed a law ratifying a mutual defense treaty with North Korea, while North Korean media reported Monday that Kim Jong Un had also signed the treaty into law.

The pact is the most significant agreement signed by Russia and North Korea in decades and is seen as something of a revival of their 1961 Cold War-era mutual defense pledge. It also consolidates the Kim regime’s powerful link with a world power that wields a veto on the UN Security Council.

Russia and North Korea have forged increasingly friendly ties since Moscow launched its full-scale invasion of Ukraine in 2022. North Korea has one of the world’s largest militaries with 1.2 million soldiers, but most of its troops lack combat experience.

Zelensky said last week that 11,000 North Korean soldiers were now in the region.

Separately, a Ukrainian commander told CNN Sunday that North Korean troops were taking part in direct combat operations in Kursk, as well as defensive operations in the neighboring Belgorod region of Russia and in Russian-occupied Ukrainian territories.

North Korean troops deployed to Russia’s Kursk region have fought Kyiv’s forces on the battlefield, Ukrainian President Volodymyr Zelensky said Thursday, adding that the clashes resulted in fatalities.

Kyiv braces for second Trump presidency

Ukraine is once again finding itself in a difficult position. Russia has been launching near daily waves of long-range drone strikes on its cities while also struggling to hold back Russian advances at multiple locations along the more than 600-mile (1,000-kilometer) frontline.

Over the weekend, Russia and Ukraine exchanged record numbers of drone strikes, with Moscow launching a total of 145 drones on Saturday night.

Ukraine meanwhile fired an unprecedented number of drones towards Russia’s capital overnight on Saturday into Sunday.

At the same time, Kyiv is trying to gauge the impact of Donald Trump’s victory in the US election last week. Trump has previously said he could end the conflict in 24 hours and in September he declared: “I think it’s in the US’ best interest to get this war finished and just get it done.”

CNN’s Alex Marquardt, Maria Kostenko and Mitchell McCluskey contributed to this report.