Russia’s military has announced it is “continuing to repel” a Ukrainian incursion into the western Kursk region, marking a surprise attack now entering its fourth day. According to the Russian defense ministry, Ukraine has lost over 280 military personnel in the past 24 hours, though this claim has not been independently verified.

Reports indicate that Ukrainian forces have penetrated more than 10km (six miles) into Russian territory, marking Kyiv’s deepest cross-border advance since Moscow’s full-scale invasion in February 2022. While Ukraine has not officially acknowledged the incursion, President Volodymyr Zelensky stated on Thursday that Moscow must “feel” the consequences of its actions.

In a separate incident, Ukraine’s military claimed to have struck a military airfield deep within Russia, reportedly destroying warehouses with guided bombs. The Ukrainian military described a significant fire and multiple explosions at the Lipetsk airfield, located more than 350km (217 miles) from Ukraine’s border, following the overnight attack.

Authorities in Lipetsk have declared a state of emergency in the area, confirming detonations at an “energy infrastructure facility” and evacuating residents from four nearby villages.