Loud explosions have been heard in parts of south-west Russia and occupied Crimea overnight.
Russian officials say the border city of Belgorod, where 25 people were killed on Saturday, came under attack again as well as Sevastopol in Crimea, where a Ukrainian missile was downed.
In recent days the aerial war between Russia and Ukraine has intensified.
Ukrainian President Volodymyr Zelensky says Russia used some 300 missiles and 200 drones over five days.
Russia launched its biggest aerial bombardment of the invasion late last week, killing more than 40 people. Ukrainian forces responded with the attack on Belgorod in which more than 100 people were also injured.
In his nightly address on Tuesday, Mr Zelensky said Russia had fired "almost one hundred missiles of various types" that day. They had, he said, been "specifically calculated by the enemy to cause as much damage as possible".
Speaking to the BBC later, the Ukrainian ambassador to the US, Oksana Markarova, said Russia's recent bombardment was "not something that came as a surprise" - but that for Ukraine to win the war they needed more weapons to respond and "just clearly send a message to Russia that they should stop".