Russia fighting intense battles against major Ukrainian incursion

• Russia imposes security regime on border regions
  • Ukrainian forces battling inside Russia
  • Belarus destroys suspected drones from Ukraine
  • IAEA calls for restraint around Kursk nuclear station

MOSCOW, Aug 10 (Reuters) - Russia was fighting intense battles on Saturday against thousands of Ukrainian troops as deep as 20 km (12 miles) inside the Kursk region after Ukraine's biggest attack on Russian sovereign territory since the start of the war in 2022.

Ukrainian forces rammed through the Russian border early on Tuesday and swept across some Western parts of Russia's Kursk region, a surprise attack that may be aimed at gaining leverage in possible ceasefire talks after the U.S. election.

Supported by swarms of drones and heavy artillery fire, Ukrainian units moved quickly to carve out a sliver of the Western Russian territory beside the border while sabotage units pierced deeper inside Russia, according to Russian war bloggers.

"The armed forces continue to repel the attempted invasion by the Ukrainian armed forces," Russia's defence ministry said on Saturday, adding that intense battles were focused around Malaya Loknya, Olgovka and Ivashkovskoye, settlements around 10-20 km inside Russia.

In a sign of the gravity of the situation, Russia imposed a sweeping security regime in three border regions on Saturday while Belarus said it had repelled what it thinks was a major drone attack from Ukraine.

President Vladimir Putin cast the Ukrainian attack as a major provocation and though Russia's top general, Valery Gerasimov, said on Wednesday that Ukraine's incursion had been halted, Russia has thus far failed to push the Ukrainian forces back over the border.

Russian military bloggers said on Saturday the situation had stabilised after Russia rushed in forces to halt the surprise advance, though they said Ukraine was swiftly building up forces.

The Ukrainian attack has prompted some in Moscow to question why Ukraine was able to pierce the Kursk region so easily after more than two years of the most intense land war in Europe since World War Two.