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.

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

Ukraine launched a new offensive in Russia's Kursk region Sunday, Moscow and Kyiv said. Ukrainian forces had captured about 500 square miles of the western Russian province in a surprise incursion in August,