The surprise attack seeks to reverse Ukraine’s decreasing hold of the region. Since Kyiv’s forces gained partial control of Kursk following a daring cross-border assault last August, Russian troops, aided by North Korean soldiers, have halved the territory held by Ukraine, albeit while suffering thousands of casualties.

As Ukrainian forces mount a new offensive in Russia’s Kursk region, U.S. Secretary of State Antony Blinken on Monday said that success in this region would improve Kyiv’s bargaining position in any future ceasefire negotiations.

Russia claims that its forces have captured the front-line town of Kurakhove in eastern Ukraine's Donetsk region. The town has borne the brunt of Russian advances in recent months and is a stepping-stone to the key logistical hub of Pokrovsk.