“At most, we controlled about 1,376 square kilometres, now of course this territory is smaller. The enemy is increasing its counterattacks,” the source told Reuters.

“Now we control approximately 800 square kilometres. We will hold this territory for as long as is militarily appropriate.”

Ukraine first gained a foothold in Kursk Oblast during a surprise incursion into the Russian region in early August. Since then, Russia has launched extensive counterattacks in an effort to take back the region.

NATO allies believe that Russian President Vladimir Putin is aiming to recapture territory lost in Kursk Oblast before US President-elect Donald Trump’s inauguration on Jan. 20, The Telegraph reported, hoping to gain leverage in future peace negotiations.

The source added that nearly 60,000 Russian army personnel are currently stationed in Kursk Oblast, planning to reach the border with Sumy Oblast to create a “buffer zone” there, as Ukraine looked to do with its incursion into Kursk Oblast.

Kyiv has previously claimed that about 11,000 North Korean soldiers have joined the counteroffensive in Kursk, with the General Staff source noting that the majority of North Korean soldiers was finalizing training along Russian forces.

As Russia’s attempt to take back Kursk continues to progress, Russia has also intensified its attacks along the eastern front in recent weeks, putting Ukrainian forces under mounting pressure as they struggle to defend key positions.

In total, almost 580,000 Russian soldiers are participating in combat against Ukraine, Vadym Skibitskyi, the deputy head of Ukraine’s military intelligence agency (HUR), told Interfax Ukraine.

Speaking during a meeting at the Kremlin with the leadership of the Defense Ministry and defense industry representatives, Putin outlined that the Oreshnik missile system, one of Russia’s latest military advancements, is not a modernization of an old Soviet weapon.

Instead, it is a new development based on cutting-edge hypersonic technology and modern materials.

“It is the result of work done in the conditions of New Russia,” Putin said, highlighting that the system was created to meet contemporary defense needs.

Putin confirmed that several Oreshnik systems are currently undergoing testing in Russia, and that the decision to embark on mass production had already been articulated.

“You can assume that the decision on production has been made. In fact, it is organized,” he added.

More of the missile systems are expected to be delivered to Russia’s Strategic Missile Forces in the coming months.

The first combat use of the Oreshnik missile took place on Thursday, when it was used to strike a Ukrainian defense facility in Dnepropetrovsk. The target was Yuzhmash, one of Ukraine’s largest defense-industrial facilities inherited from the USSR that produces missile equipment and other weapons.

Putin stated that the use of the missile was in response to Kiev’s attacks inside Russia with Western-supplied long-range weapons such as American ATACMS and British Storm Shadow missiles.

The Oreshnik is described as a medium-range, hypersonic weapon designed for high precision strikes. According to the Defense Ministry, “all warheads” of the missile “reached the target” during this week’s deployment.

The president praised the missile’s successful test and combat deployment, expressing admiration for the speed at which the system had been developed.

Putin also emphasized the importance of continuing testing and increasing production rates.

“I congratulate the military on the successful tests and support the adoption of the system,” he noted.

This initiative is in response to Russia launching a new type of intermediate-range ballistic missile (IRBM) called “Oreshnik” against Dnipro, east Ukraine, on Thursday.

The attack came in the wake of what appeared to be Ukraine’s first successful strike of a military target inside Russia using the US-supplied ATACMS missiles.

The IRBM missiles are only guided during the initial stages of launch, so they can be less accurate than cruise missiles, but have the advantage of reaching incredibly high speeds — sometimes more than 3,200 kilometers per hour — as they approach their targets.

“The Minister of Defense of Ukraine is already holding meetings with our partners regarding new air defense systems—precisely such systems that are capable of protecting lives from new risks,” Zelensky wrote on Telegram.

He emphasized that Russia’s testing of experimental missiles constitutes an international crime and criticized Moscow for escalating aggression despite global calls for peace.

Zelensky promised to share details about the missile attack on Dnipro with international media, so that the full extent is known to global audiences.

The Ukrainian leader has also stated that the deployment of an ICBM against Dnipro shows that Russian President Vladimir Putin “is using Ukraine as a testing ground”.

The comments came after Putin confirmed his country had launched its “newest missile”, an IRBM called “Oreshnik”, in an attack on Dnipro. He the attack was in response to Ukraine targeting facilities in Russian oblasts using Western-supplied long-range missiles.

NATO spokesperson Farah Dakhlallah has said Russia’s use of a purported new ballistic missile “will not change the course of the conflict, or deter NATO allies from supporting Ukraine”.

“The Russian attack on Dnipro is yet another example of Russia’s attacks on Ukrainian cities,” Dakhlallah stressed.