At least 6 killed, dozens injured in Russian strikes in southern Ukraine, officials say

A 10-year-old girl and her mother were among four civilians killed in a Russian airstrike on Ukrainian President Volodymyr Zelenskyy's home town on Monday, officials said, while his forces reported new incremental gains along the front line.

Zelenskyy, who had described Sunday as "a good day, a powerful day" at the front, said Monday's Russian strikes had hit a residential and a university building in Kryvyi Rih, the steel city where he grew up, far from the front line.

"This terror will not frighten us or break us. We are working and saving our people," he said on the Telegram app.

A senior defence official said earlier that Ukrainian forces had recaptured nearly 15 square kilometres of land over the past week from Russian troops, who occupy almost one-fifth of Ukraine in its east and south.

The gains make a total of more than 200 square kilometres retaken in the south since the Ukrainians launched a major Western-backed push against Russian forces early last month, Deputy Defence Minister Hanna Maliar said on the Telegram messaging app.

Russian Defence Minister Sergei Shoigu told a military conference Ukraine was "desperately hurling new forces" into attacks on Russian positions, but had failed to advance and was wasting billions of dollars of Western weaponry.

Reuters could not immediately verify either side's report.

In Kryvyi Rih, smoke billowed from a gaping hole smashed in the side of a nine-storey residential building, and another four-storey building was almost levelled, video footage posted by Zelenskyy showed.

Emergency services said at least 43 people had been wounded.

"Tragic news. Four people have already died in Kryvyi Rih," Serhiy Lysak, the regional governor, wrote on Telegram. The city's mayor Oleksandr Vilkul said they included a girl, 10, and her 45-year-old mother and there could be as many as eight people trapped under the rubble.

Two more civilians were reported killed in the southern Ukrainian city of Kherson, now on the front line after being recaptured from Russian forces in November.

An early-morning rocket attack killed a 60-year-old utility worker and wounded four others as they were out on the street doing their jobs, the regional military administration said.

A 65-year-old man driving his car was badly wounded in the second strike and died as an acquaintance tried to rush him to hospital, regional governor Oleksandr Prokudin said on Telegram.

In Ukraine's Russian-occupied eastern Donetsk region, the Russian-installed governor said two people had been killed and four injured in Ukrainian shelling of what he said was a civilian bus in Donetsk city, the regional capital.