Russia's defence ministry said it had downed 635 Ukrainian drones during the night.
The acting governor of Russia's border region of Belgorod, Alexander Shuvayev, said a Ukrainian drone struck an area next to a playground, killing one child and injuring two.
Maria Lvova-Belova, Russia's commissioner for children's rights, was quoted by Russian news agencies as saying that the strike was "another inhumane terrorist act" by Ukraine.
Ukrainian drones attacked a Wildberries warehouse in the Samara region, about 800km from Ukraine's most advanced military positions, Samara governor Vyacheslav Fedorishchev said.
Ukrainian forces have been hitting deeper inside Russia as they expand strikes on economic and energy targets, aiming to undermine Russia's ability to wage its more than four-year-old war in Ukraine.
They have attacked about a dozen Wildberries sites since July 18 in an attempt to disrupt the operations of the company, a linchpin of the consumer economy often described as Russia's version of Amazon.
A strike on a residential building in the neighbouring Saratov region killed two people in the city of Engels, Governor Roman Busargin said.
Civil infrastructure was damaged both in Engels and in the city of Saratov, he said.
Both Saratov city, which hosts a major oil refinery, and Engels, home of a military air base, have come under repeated Ukrainian attack in recent years.
Ukrainian President Volodymyr Zelenskiy confirmed Ukrainian attacks on targets in Russia, naming the Saratov oil refinery and the Engels military air base.
He thanked the Ukrainian armed forces and said that Ukraine was taking the war back to where it had come from.
Ukraine's military said its forces had also struck an oil depot in the western Kaluga region.
Three people were killed and two injured in a drone attack on the Udmurtia region of Russia, acting governor Olga Abramova said.
In the border region of Belgorod, three people were killed and five injured in Ukrainian strikes, the local task force reported.
The governor of Russia's Bashkortostan region, Radiy Khabirov, said air defence units had repelled a massive drone attack on industrial facilities.
One of the drones was shot down over the industrial area of the regional capital of Ufa and a fire was being put out, he said.
Russia's defence ministry said its forces had struck infrastructure and two vessels with military cargo in the Ukrainian port of Mykolaiv, as well as a vessel carrying military supplies in the Black Sea.
In the southeastern Ukrainian city of Zaporizhzhia, regional governor Ivan Fedorov said Russian-launched glide bombs killed one person and injured 21.
with DPA
