STORY: This video appears to show damage caused by debris from a Ukrainian missile that officials in the Russian city of Kursk say injured at least 13 people early on Sunday (August 11).
That's after President Volodymyr Zelenskiy acknowledged for the first time that Ukrainian forces were fighting in the surprise cross-border offensive.
In his nightly video address on Saturday (August 10), Zelenskiy said he had discussed with Ukraine's top commander the actions to "push the war onto the aggressor's territory".
"Ukraine is proving that it can indeed restore justice and ensure the necessary pressure on the aggressor."
Sunday marked the sixth day of intense battles amid Kyiv's largest incursion onto Russian territory since the start of the war.
Russian President Vladimir Putin cast the Ukrainian attack as a major provocation.
Russia imposed a sweeping security regime in three border regions on Saturday, while its ally Belarus sent more troops to its border with Ukraine.
In the city of Kursk, footage showed a damaged nine-storey apartment building on fire.
It was not clear whether there was further damage from the destroyed Ukrainian missile.
Reuters was able to confirm the location of the video but could not independently verify the date it was filmed.
Meanwhile, Russia's defense ministry said on Sunday it had destroyed 14 Ukrainian drones and four tactical ballistic missiles overnight over the Kursk region.
Additionally, 18 drones were said to have been destroyed over other Russian regions that Ukraine frequently attacks.
