Days after Ukraine began a surprise military incursion into Russia's Kursk border region, President Volodymyr Zelenskyy has broken the government's silence on it by indirectly acknowledging the ongoing military actions to "push the war out into the aggressor's territory."Video above: Freed Americans touch down on U.S. soil following historic, multinational prisoner swapZelenskyy's comment came in his nightly address late Saturday.Ukraine's incursion into Russia continued for a sixth day Sunday. It's the largest such attack since Moscow launched its full-scale invasion on Feb. 24, 2022, and is unprecedented for its use of Ukrainian military units on Russian soil. Ukraine's raid into Russia caught Moscow unaware and was an embarrassment to Russian military leaders who have scrambled to contain the breach.The Russian Defense Ministry said in a statement on Sunday that its forces engaged Ukrainian troops in Tolpino, Zhuravli and Obshchy Kolodez, the official Tass news agency reported. Tolpino is 25 kilometers (15 miles) from the Ukrainian border.The evacuation of civilians living in Russia's border areas with Ukraine continued Sunday. Russian state television aired footage of evacuees at a tent camp in the city of Kursk. According to the report by RTR, more than 20 temporary accommodation centers have been set up in the region.The exact aims of the operation remain unclear, and Ukrainian military officials have adopted a policy of secrecy, presumably to ensure its success. Military experts have said that it is likely intended to draw Russian reserves away from the intense fighting in Ukraine's eastern Donetsk region, while a presidential adviser suggested that it may strengthen Kyiv's hand in any future negotiations with Russia.But Russian Foreign Ministry spokeswoman Maria Zakharova said Sunday that Ukraine "understands perfectly well" that the recent attacks "make no sense from a military point of view.""The Kyiv regime is continuing its terrorist activity with the sole purpose of intimidating the peaceful population of Russia," she said.Fire at the Zaporizhzhia power plantMeanwhile, a fire in the vicinity of the Russian-occupied Zaporizhzhia power plant was reported by Ukrainian officials late Sunday. According to Yevhen Yevtushenko, the head of the military administration of Nikopol, which is across the river from occupied Enerhodar, where the plant is located, Russian forces set fire to automobile tires in the cooling towers to make it appear as though a fire had broken out."Perhaps this is a provocation or an attempt to create panic in the settlements on the right bank of the former reservoir," he said. Zelenskyy also said Russia was using the plant to blackmail Ukraine and playing on Western fears of escalation. Yevhen Balytskyi, the Russia-appointed governor of the occupied Zaporizhzhia region, accused Ukrainian forces of shelling the plant and causing the fire. He provided no evidence for the claim.Overnight drone and missile attacksOvernight into Sunday, a Russian drone and missile barrage on Kyiv killed two people, including a 4-year-old boy. Russia attacked Ukraine with four ballistic missiles and 57 Shahed drones, Ukraine's air force said. Air defenses shot down 53 of the drones.The bodies of a 35-year-old man and his son were found under rubble after missile fragments fell on a residential area in Kyiv's suburban Brovary district, according to the State Emergency Service of Ukraine. Another three people in the district were wounded in the attack. It was the second time this month that Kyiv has been targeted, said Serhii Popko, head of the Kyiv City Military Administration.Popko said ballistic missiles didn't reach the capital, but that suburbs took the hit while drones aiming for the capital were shot down.In Russia, Kursk's regional governor said that a Ukrainian missile shot down by Russian air defenses fell on a residential building, wounding 15 people. The Russian Defense Ministry said that 35 drones were shot down overnight over the Kursk, Voronezh, Belgorod, Bryansk and Oryol regions.Ukraine hasn't commented on the Sunday drone attacks inside Russia. But they come as Ukraine has increased the pace of similar drone attacks largely targeting military infrastructure and oil depots in recent weeks.Belarus says it's sending forces to its borderMeanwhile, Belarus said that it was sending more troops to its border with Ukraine on Saturday, saying Ukrainian drones had violated its airspace as part of Kyiv's military incursion into Russia's Kursk region.Authoritarian leader Alexander Lukashenko said Belarusian air defense forces destroyed dozens of targets flying from Ukraine over the Mogilev region, which borders Russia, on Friday evening."The Ukrainian armed forces violated all rules of conduct and violated the airspace of the Republic of Belarus. In the eastern direction, very close to us in the Kostyukovichi district," Lukashenko said at a meeting in Minsk on Saturday.Belarusian Defense Minister Viktor Khrenin said the government regards the violation of its airspace as a provocation and is "ready for retaliatory action."