As dawn broke over the western Russian region of Belgorod, a growing thrum could be heard near its heavily fortified border with Ukraine.

The sound came from a column of tanks and fighting vehicles storming across muddy fields, carving a path through minefields and lines of dragon’s teeth barricades.

It was the start of a new incursion into Russian territory.

That was two weeks ago and, despite the Kremlin’s claims that the attack was thwarted, Ukraine’s forces are moving forward and steadily capturing ground.

The battle plan has been closely guarded, and it is still unclear whether the Belgorod incursion was intended as a brief raid or a longer-term operation.

There is currently fierce fighting in the villages of Demidovka, Prilesye and Popovka, according to the Institute for the Study of War, a US think-tank.

Ukraine has also been carrying out a series of precision air strikes, targeting command posts, bridges, helicopters and depots.