Until just over a week ago, Artem Kariakin and his unit were making regular trips across Ukraine's border into the Russian town of Sudzha..

He shows me video taken with a phone of their very last trip, as Ukrainian forces retreated from Russia's Kursk region. It shows them making their way past dozens of burnt out military and civilian vehicles.

A soldier armed with a shotgun, their last line of defence, scans the horizon for Russian drones. Out of nowhere, one flies towards the back of their truck. Sparks fly, but they keep on going.

Artem says they were lucky - the explosive charge was not big enough to stop them.

Another truck nearby was less fortunate. It was already in flames.

Artem admits Ukraine's retreat from Sudzha, the largest town Ukraine held in Kursk, was "not well organised".

"It was pretty chaotic," he tells me. "Many units left in disarray. I think the problem was the order to withdraw came too late."