KYIV, Ukraine >> Ukraine has lost over 40% of the territory in Russia’s Kursk region that it seized in a surprise incursion in August as Russian forces have mounted waves of counterassaults, a senior Ukrainian military source said.

Ukraine has now lost more than 40% of the territory of Kursk Oblast, which it has controlled since August, as a result of Russian counterattacks, says a Reuters source in the General Staff of the Ukrainian Armed Forces.

Ukraine has lost over 40% of the territory in Russia's Kursk region that it seized in a surprise incursion in August as Russian forces have mounted waves of counter-assaults, a senior Ukrainian military source said.

The Kursk offensive was the first ground invasion of Russia by a foreign power since World War Two and caught Moscow unprepared.

Meanwhile, Ukraine's surprise incursion into Russia's Kursk region is faltering. Russian troops have pushed Kyiv's offensive backwards. Experts have questioned the success of the offensive, with one calling it a "strategic catastrophe" given manpower shortages faced by Ukraine.

Ukraine has lost over 40% of the territory in Russia's Kursk region that it rapidly seized in a surprise incursion in August as Russian forces have mounted waves of counter-assaults, a senior Ukrainian military source said.

Ukraine has lost over 40 percent of the territory in Russia's Kursk region that it rapidly seized in a surprise incursion in August as Russian forces have mounted waves of counterassaults, a senior Ukrainian military source has said.

Ukraine has lost over 40% of the territory in Russia's Kursk region that it rapidly seized in a surprise incursion in August as Russian forces have mounted waves of counter-assaults, a senior Ukrainian military source said.

Of the territory Ukraine captured in a surprise attack in Russia's Kursk oblast in August, it has already lost 40 percent again. An army source told the Reuters news agency. “At the maximum, we had control of 1,