Overnight into Sunday, a Russian drone and missile barrage on Kyiv killed two people including a 4-year-old boy, while in Russia, Kursk's regional governor said 13 people were wounded when a Ukrainian missile shot down by Russian air defences fell on a residential building.

The bodies of a 35-year old man and his son were found under rubble after fragments of missiles fell on a residential area in Kyiv's suburban Brovary district, according to Ukraine's State Emergency Service on Sunday. Another three people in the district were also injured in the attack.

Serhii Popko, head of the Kyiv City Military Administration said it was the second time this month Kyiv was targeted.

Popko said ballistic missiles did not reach the capital but that suburbs took the hit, while drones aiming for the capital were shot down.

Ukraine's incursion continued for a sixth day on Sunday and is unprecedented for its use of Ukrainian military units on Russian soil. The exact aims of the operation remain unclear and Ukrainian military officials have adopted a policy of secrecy, presumably to ensure its success.

In Russia, the Defence Ministry said 35 drones were shot down overnight over the Kursk, Voronezh, Belgorod, Bryansk and Oryol regions.

Ukraine has not commented on the Sunday drone attacks inside Russia. But it comes as Ukraine has increased the pace of similar drone attacks largely targeting military infrastructure and oil depots in recent weeks.