Russia has clawed back territory from Ukrainian troops in the western Kursk region as North Korean forces are anticipated to join the front-line battles shortly.

The Institute for the Study of War (ISW) revealed on Saturday that Moscow's soldiers "recently advanced" in the segment under Ukrainian control in Kursk.

The bold early August offensive by Kyiv into Kursk was the most substantial move into Russian-held land since the outbreak of the war in February 2022 - it marks the first incursion by another state onto Russian soil since the Second World War.

Ukrainian actions have concentrated near the town of Sudzha, secured by Kyiv barely a week following the start of its campaign, and spreading towards Korenevo, situated to the northwest.

Although Russia has recaptured territories in the proximity of Korenevo, Sudzha remains in Ukraine's grip. Geolocated footage indicates that Russian advances have been made to the southeast of Korenevo, as per the ISW's findings.

A high-ranking but unidentified military official from Kyiv's General Staff told Reuters that Ukraine had relinquished over 40 percent of its acquired ground in Kursk.

At the height of their control, Ukrainian units held approximately 531 square miles, which, according to the source, has now diminished to around 309 square miles.

Russia has amassed nearly 60,000 troops in Kursk, according to the source, who also revealed that Moscow is intensifying its counterattacks.

Ukraine has acknowledged that Russia has launched counteroffensive operations aimed at weakening Kyiv's control in the region over the past few months.

However, despite these efforts, Russia has made slow progress in pushing opposition forces back to the border, whereas it has consistently gained ground in eastern Ukraine, advancing towards the strategic transit hub of Pokrovsk.

Intelligence reports from South Korea, the US, and Ukraine suggest that up to 10,000 North Korean soldiers have been deployed to Kursk to support Moscow's war effort.

These fighters are allegedly dressed in Russian military uniforms and integrated into the Kremlin's existing military forces.

In a statement posted on Telegram in early November, Syrskyi said, "Russia's own troops are not enough" for operations in Kursk. "So they are trying to attract troops from North Korea there".

Reports indicate Pyongyang has been instrumental in bolstering the Russian military campaign by sending a substantial cache of missiles and an arsenal of munitions.

An intelligence source from South Korea disclosed that Russia had reciprocated with air defence systems and "economic aid in various forms" to North Korea.