Ukraine and Russia exchanged drone and artillery fire on Thursday, leaving at least seven dead and more than a dozen wounded, regional officials on both sides of the front line announced.

The uptick in civilian deaths came as Russian forces press hard in the eastern Donetsk region ahead of May 9, the day when Moscow hails the Soviet Union's victory in World War II.

A Ukrainian attack drone left two dead in the southern region of Zaporizhzhia and two more were killed by Ukrainian artillery fire in the southern Kherson region, officials said.

The Kremlin claimed to have annexed both regions in late 2022 even though Russian forces are still battling to gain full control over them.

"A man and a woman were killed as a result of a strike on a civilian car. Their four young children were orphaned," the Russian-installed head of Zaporizhzhia, Yevgeny Balitsky, wrote on social media.

He said the children would be taken into care and provided with psychological assistance.

The Russian head of the Kherson region, Vladimir Saldo, said separately that two more people were killed by Ukrainian fire in the village of Dnipryany. 

The two frontline regions saw intense bouts of fighting in 2022 and the summer of 2023, when Ukraine launched a counteroffensive that failed to meet expectations in Zaporizhzhia.

The brunt of the fighting has since moved to the eastern Donetsk region, which is also claimed by Moscow as Russian territory.

The Ukrainian head of the Donetsk region, Vadim Filashkin, said three people had been killed in separate bouts of shelling in the villages of Udachne, where two people were killed, and in Kurakhivka, where one person was killed.

"The final consequences of the shelling have yet to be determined," he said.  

Later on Thursday, a Russian attack on a railway station in the northeastern Kharkiv region injured at least 10 people, Ukrainian governor Oleg Synegubov said.

In the Russian border region of Bryansk, a Ukrainian drone hit a bus, injuring four people, the Russian governor of the region said.

And in the Russian-controlled part of Ukraine's Zaporizhzhia region, a Ukrainian strike on a multi-storey residential building injured at least three, Balitsky said on Telegram.