Russia's ability to continue fighting in the war with Ukraine may be in jeopardy as it suffers highest rate of military personnel losses in the Ukraine war.

The claim, which drew no response from Ukrainian authorities, came a day after the Russian Defense Ministry said Ukrainian forces had pressed new attacks in Russia’s Kursk border region.

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.

Ukraine has launched a counterattack in the southern Russian border region of Kursk, warning that Russia is “getting what it deserves.”

It comes as Ukraine's president says only the US can provide security guarantees leading to an end to the war.