Ukrainian service members ride a M113 armoured personnel carrier, amid Russia's attack on Ukraine, near the front line city of Bakhmut, Donetsk region, Ukraine June 9, 2023. [Source: Reuters]

Counterattacking Ukrainian forces have advanced up to 1,400 metres at a number of sections of the front line near the eastern city of Bakhmut in the past day, a military spokesman said.

The advance is the latest in a series of similar gains reported this week by Kyiv near Bakhmut, which Russia said it had fully captured last month after the bloodiest and longest battle since it began its full-scale invasion in February 2022.

Serhiy Cherevaty, the official, said in televised comments that Russian forces were themselves trying to counterattack but that they had not been successful.

Ukrainian forces, he said, had inflicted heavy Russian troop casualties and destroyed military hardware in the area.

Reuters was not able to independently verify that assertion or the situation on the battlefield.

Moscow and Kyiv both reported heavy fighting in Ukraine on Friday, with bloggers describing the first sightings of German and U.S. armour, signalling that Ukraine’s long-anticipated counterattack was underway.

Russia, which has built extensive fortifications in Ukraine’s occupied east and south, said this week that a big push by Kyiv had failed to break through Russian lines.

Britain’s Ministry of Defence said that Ukrainian forces have penetrated the first line of Russian defences in some areas but that Kyiv’s progress had been slower in others.

Officials in Ukraine, which has been poised to launch a broad counteroffensive for weeks, denies its much-anticipated push has begun and says that when it does it will be obvious.