Ukraine’s president Volodymyr Zelensky has appeared to confirm a Ukrainian incursion into Russia’s Kursk border region.
The cross-border operation which began six days ago, the largest since the war began, was an unprecedented use of military units on Russian soil, causing embarrassment to Russian military leaders and the Kremlin.
Speaking in his nightly address on Saturday, Mr Zelensky indirectly acknowledged ongoing military action to "push the war out into the aggressor's territory".
The exact aims of the Kursk operation remain unclear and Ukrainian military officials have adopted a policy of secrecy.
But military experts have said that it is probably intended to draw Russian reserves away from the intense fighting in Ukraine's eastern Donetsk region, while a presidential adviser suggested it may strengthen Kyiv's hand in any future negotiations with Russia.
Kursk acting governor Aleksei Smirnov said on Sunday that "Ukrainian sabotage and reconnaissance group" entered the Belovsky district the previous day, but that the situation had been "stabilised".
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.
Meanwhile, Belarus said on Saturday that it is sending more troops to its border with Ukraine, saying Ukrainian drones have violated its airspace as part of Kyiv's military incursion into Russia's Kursk region.
It comes as a Russian drone and missile barrage on Kyiv killed two people overnight - a man and his four-year-old son.
In Russia, Kursk's regional governor said a Ukrainian missile shot down by Russian air defences fell on a residential building, injuring 13 people.
Russia attacked Ukraine with four ballistic missiles and 57 Shahed drones, Ukraine's Air Force said. Air defences shot down 53 drones.
The bodies of a 35-year old man and his young 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 area were injured in the attack.
Serhii Popko, head of the Kyiv City Military Administration, said it was the second time this month that Kyiv has been targeted.
He said ballistic missiles did not reach the city centre but suburbs took the hit, while drones aiming for the capital were shot down.
Mr Zelensky said it appeared Russia had used a North Korean missile in the strike.
Ukraine and the US have previously said Russia has used North Korean missiles in the war.
