Ukraine has reportedly lost more than 40% of the territory it quickly captured in Russia‘s Kursk region during a surprise incursion in August, as Russian forces have launched multiple counter-offensives, according to a senior military official from Ukraine.

The official, who is part of Ukraine‘s General Staff, indicated that Russia has mobilized approximately 59,000 troops to the Kursk area since Ukrainian forces executed their rapid advance, which took Moscow by surprise two and a half years into its full-scale invasion of Ukraine.

“Initially, we controlled around 1,376 square kilometers (531 square miles), but that area has now diminished. The enemy is intensifying its counterattacks,” the official stated.

“Currently, we maintain control over roughly 800 square kilometers (309 square miles). We will defend this territory for as long as it is strategically viable.”

The Kursk offensive marked the first ground invasion of Russia by a foreign entity since World War II, catching Moscow off guard.

Kyiv’s offensive in Kursk was intended to halt Russian advances in eastern and northeastern Ukraine, compel Russia to withdraw its forces that are progressively moving eastward, and enhance Ukraine’s position in potential future peace talks.

However, Russian troops continue to make steady progress in the eastern Donetsk region of Ukraine.

A source from the Ukrainian General Staff confirmed that approximately 11,000 North Korean soldiers have arrived in the Kursk area to support Russia, although most of these troops are still completing their training.

The Russian Defence Ministry has not yet responded to a request from Reuters regarding Kyiv’s latest evaluation of the situation in the Kursk region. Reuters has been unable to independently verify the numbers or claims provided.

Moscow has not confirmed or denied the presence of North Korean troops in Kursk.

On November 11, Ukraine’s armed forces chief stated that their struggling troops are not only facing elite Russian reinforcements in Kursk but are also working to bolster two encircled fronts in eastern Ukraine while preparing for a potential infantry assault in the south.

Russian Offensive in Eastern Ukraine Poses Significant Threat

According to a source from the General Staff, the Kurakhove area currently represents the most critical threat to Kyiv, with Russian troops advancing at a rate of 200-300 meters per day. They have successfully penetrated certain regions, utilizing armored vehicles supported by anti-drone systems.

Kurakhove serves as a crucial link to the vital logistical center of Pokrovsk in the Donetsk region.

The Ukrainian General Staff estimates that Russia has approximately 575,000 soldiers engaged in the conflict in Ukraine, with plans to bolster this number to around 690,000.

Russia does not publicly disclose its troop levels, and Reuters has been unable to independently verify these statistics.

As Ukraine confronts a larger and more well-equipped adversary, it has focused on disrupting Russian logistics and supply lines by targeting weapons and ammunition depots, airfields, and other military installations deep within Russian territory.

Earlier this month, Ukraine received greater latitude to act after President Joe Biden reportedly lifted his objections to Kyiv using U.S.-supplied missiles against targets deep within Russia, a move prompted by North Korea’s involvement in the conflict.

Last week, Ukraine launched U.S. ATACMS and British Storm Shadow cruise missiles into Russian territory, with one ATACMS strike hitting an arms depot located approximately 110 kilometers (70 miles) inside Russia.

In response, Moscow has pledged to retaliate against what it perceives as an escalation supported by Ukraine’s Western allies. On Thursday, Russia fired a new medium-range ballistic missile into the Ukrainian city of Dnipro, likely serving as a warning to NATO.

Ukrainian officials are currently in discussions with the United States and Britain about acquiring new air defense systems designed to shield Ukrainian cities and civilians from emerging long-range aerial threats.

According to a source from the Ukrainian General Staff, the military has taken steps to enhance air defenses over the capital, Kyiv, and is planning similar measures for the northern city of Sumy and Kharkiv in the northeast, both of which are close to the front lines.

Currently, Russia occupies about one-fifth of Ukraine, and President Vladimir Putin has expressed a desire for Kyiv to abandon its aspirations to join the NATO military alliance and withdraw from four regions of Ukraine that he partially controls—demands that Kyiv has firmly rejected as equivalent to surrender.