A Ukrainian serviceman of the 68th Oleksa Dovbush hunting brigade runs to his position. Photo / AP

Russia and Ukraine are suffering high numbers of military casualties as Ukraine fights to dislodge the Kremlin’s forces from occupied areas in the early stages of its counteroffensive, British officials said on Sunday.

Russian losses are probably at their highest level since the peak of the battle for Bakhmut in March, UK military officials said in their regular assessment.

According to British intelligence, the most intense fighting has centred on the southeastern Zaporizhzhia province, around Bakhmut and further west in Ukraine’s eastern Donetsk province. While the update reported that Ukraine was on the offensive in these areas and had “made small advances,” it said that Russian forces were conducting “relatively effective defensive operations” in Ukraine’s south.

The Ukrainian military said in a regular update Sunday morning that over the previous 24 hours Russia had carried out 43 airstrikes, four missile strikes and 51 attacks from multiple rocket launchers.

According to the statement by the General Staff, Russia continues to concentrate its efforts on offensive operations in Ukraine’s industrial east, focusing attacks around Bakhmut, Avdiivka, Marinka and Lyman in the country’s Donetsk province, with 26 combat clashes taking place.

Donetsk regional Gov. Pavlo Kyrylenko said that two civilians were killed, with a further three wounded in the past day.

Ukrainian officials said Russian forces also launched airstrikes on other regions of the east and south of the country.

One civilian was killed and four more wounded in Kherson province as a result of Russia’s attacks, said regional Gov. Oleksandr Prokudin, while Zaporizhzhia regional Gov. Yurii Malashko said one person was wounded in Russian attacks that hit 20 settlements in the province.

Serhiy Bratchuk, spokesman of the regional government in the southwestern Odesa province, said Ukrainian forces destroyed a “very significant” ammunition depot near the Russian-occupied port city of Henichesk in nearby Kherson province.

“Our armed forces dealt a good blow in the morning,” Bratchuk said in a video message on Sunday morning, posted to his Telegram channel.

Western analysts and military officials have cautioned that Ukraine’s counteroffensive to dislodge the Kremlin’s forces from occupied areas, using Western-supplied advanced weapons in attacks along the 1000km front line could last a long time.

A group of African leaders have carried out a self-styled “peace mission” to both Ukraine and Russia in recent days to try to help end their nearly 16-month-old war, but the visit ended on Saturday with no immediate signs of progress.

Meanwhile, the death toll from flooding following the destruction of the Kakhovka dam has risen to 16 in Ukrainian-held territory, Ukraine’s interior ministry said late Saturday, while Russian officials said 29 people died in territories controlled by Moscow.

Massive flooding from the destruction of the dam on June 6 devastated towns along the lower Dnieper River in the Kherson region, a front line in the war. Russia and Ukraine accuse each other of causing the breach.