Figure caption, Watch: BBC follows Ukraine's Operation Vivaldi pushing Russia back on frontlineByDan JohnsonUkraine correspondent Reporting fromnear Lyman, eastern UkraineA Russian drone zips across the computer screen, startling the commanders keeping watch over the battlefield via a live stream in their bunker. Cigarette in one hand, radio in the other, one of them calls in their own drone to bring it down and warns the soldiers below of the threat.

The men are dangerously exposed, on the long walk across open ground from their front line positions. They are being replaced after three months forcing the Russians back.

This is part of Operation Vivaldi, a Ukrainian counter-offensive which they say has liberated 277 sq km (106 square miles) in the eastern Donbas region in recent months. The name reflects the offensive's four stages, or seasons - like the Italian composer's violin concerto.

The successful assault blunted an attempted Russian pincer movement that threatened to encircle the key Fortress Belt cities still under Ukrainian control. While Russia this month pummels Ukraine from the air, crippling its energy infrastructure and killing scores of civilians across the country, at the front, it is Ukraine that has made recent gains.

Kyiv says it has inflicted heavy losses - 8,000 Russian casualties in Vivaldi alone, and close to 50,000 along the front in the month of September – and suffered few casualties in return. Image source, ReutersImage caption, The Starlink system was integrated into Ukraine's Operation Vivaldi, but this week Kyiv said restrictions had been imposed on it without warningThe Institute for the Study of War reported that pro-Russian military bloggers had acknowledged the Ukrainian advances, and expressed fears this could lead to more losses for Russia in the future.

No Russian official has publicly acknowledged the Ukrainian gains. Despite Ukraine's forward moves, Russian drones are still ever-present.

Phoenix, Commandant of the Revenge Brigade's Silver Trinity unit, tells me his men face 10 on an average day. Image caption, Ukraine's military says it has liberated 277 sq km in the eastern Donbas regionHe is fixed on the live stream as a Ukrainian snare swoops in, hovers for a few seconds and drops a net on to the drone, dragging it from the sky.

This Russian drone was for reconnaissance, but if it had locked on to the soldiers, another drone carrying explosives would have followed. This moment of peril illustrates the layers making up the modern battlefield.