Russian attacks killed four people and wounded more than a dozen others in eastern Ukraine, local authorities said.
An attack on the town of Dergachi in Ukraine's northeastern Kharkiv region killed two men aged 68 and 25 and wounded almost two dozen others, the region's governor Oleg Synegubov said.
Russian forces occupied swathes of the Kharkiv border region when they invaded in 2022, but were pushed back months later in a Ukrainian offensive that embarrassed the Kremlin.
A separate attack on Kramatorsk in Ukraine's eastern Donetsk region killed two people, the city's mayor Oleksandr Goncharenko said on Facebook.
Earlier, Ukrainian strikes killed six people, including two children, in occupied Ukraine, as well as in the Russian border regions of Belgorod and Bryansk, local authorities said.
Ukraine regularly targets Russia in retaliation for the daily bombardments it has been subjected to since the start of the large-scale Russian offensive in February 2022.
Four people, among them two children, were killed in the frontline town of Gorlivka in the occupied Donetsk region, the local Moscow-installed administration said.
"As a result of Ukrainian armed aggression in the Kalininsky district of Gorlovka, four civilians have been killed, including two children born in 2012 and 2013," mayor Ivan Prikhodko said, using a Russian spelling for the town.
During the early hours, two people died after Ukrainian drones attacked the western Russian border regions of Bryansk and Belgorod, local authorities said.
The strikes followed intense Russian bombardments that particularly targeted Kyiv over the weekend, in which Moscow used a nuclear-capable missile, killing four people and wounding more than 100, Ukrainian authorities said.
Russia said the raid was in retaliation for a Ukrainian drone attack on educational buildings in the Russian-occupied Lugansk region that left 21 dead and more than 40 injured.
The strikes come as fighting on the front remains effectively deadlocked, as both armies pound each other with swarms of explosive-laden drones.
Moscow's invasion, intended to force the swift capitulation of Kyiv, has become the deadliest conflict in Europe since World War II, killing hundreds of thousands of people on both sides and displacing millions.
Russia and Ukraine have stepped up deadly strikes in recent weeks as US-led efforts to end the war, now in its fifth year, have ground to a halt with Washington's attention diverted to the Middle East.
Ukrainian President Volodymyr Zelensky said that Ukraine had made little progress in talks with the United States on expanding production of missile defences and was working with Europe to solve the matter.
"Unfortunately, there has been no progress for a long time with America regarding the expansion of anti-ballistic missile production," he said.
"We are trying to accelerate this work in Europe, the production of our own anti-ballistic systems on the continent in sufficient quantities."
He added that Ukraine was continuing to talk to the US on how it can help Ukraine and us leadership was vital.
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Kremlin says won't pass on Russian director's call to end war to Putin
The Kremlin has said it will not pass Russian film director Andrei Zvyagitsev's message to President Vladimir Putin - made during a speech at the Cannes Film Festival - to "end the slaughter" in Ukraine.
As he accepted the Grand Prix award for his film "Minotaur" at the weekend, Mr Zvyagintsev addressed Mr Putin, saying he was the "only person" that could end the war, denouncing the Kremlin's full-scale offensive against Ukraine.
Asked if the speech was relayed to the Russian leader, Kremlin spokesman Dmitry Peskov said: "I for one, will not do it. I do not think that anyone else will do it."
Mr Peskov said Mr Zvyagintsev did "not have the right" to make such statements, as he has not criticised Kyiv.
During his speech, Mr Zvyagintsev said he knew Mr Putin would not be watching but believed "there are people in his entourage that know how to pass on these words to him".
"Millions of people from both sides of the contact line are dreaming just of one thing: for the massacres to stop," he told Mr Putin.
"You are the only person that can stop this meat grinder, Mr President of Russia. Stop this slaughter already."
Mr Zvyagintsev's film depicts a provincial Russian businessman forced to choose which employees to send to fight in Ukraine as his marriage falls apart, describing life in wartime Russia.
The Kremlin last week said it was too early to say whether "Minotaur" will be given permission for screening in Russia, which has introduced massive censorship after sending troops to Ukraine in 2022.
But Mr Zvyagintsev has said he believes many Russians will find a way to watch "Minotaur", thanks to film piracy and VPNs.
