Ukrainian forces have claimed gains in the country's east as they ramp up their counteroffensive, while the Russian military says it destroyed Western-supplied weapons.

Ukraine's military units said on social media on Sunday that they had taken back settlements in the eastern region of Donetsk. They posted a video showing soldiers hoisting a Ukrainian flag from a building heavily damaged by shelling.

A Ukrainian media report cited a military spokesperson as saying that the units produced the first achievement of their counteroffensive actions even if the gains were only local.

Russia's defense ministry said on Sunday that its forces had carried out attacks in Donetsk, the southern region of Zaporizhzhia and elsewhere. It said the Russians had destroyed 11 tanks, including three German-made Leopard tanks, and other armored vehicles.

Meanwhile, Ukraine's interior ministry said at least six people died and 35 others are missing in a massive flood caused by the collapse of the Kakhovka dam in the southern region of Kherson.

Hanna Maliar, Ukraine's deputy defense minister, blamed the Russians for the breach. She said on social media on Sunday that their aim was to block the counteroffensive and secure the necessary forces.