The unprecedented assault entered its fourth day Friday with Moscow rushing reinforcements and bombing its own territory to try to contain the Ukrainian advance.

A convoy of burnt-out military trucks, some bearing the “Z” symbol of the Kremlin’s war and appearing to contain bodies, sits along the side of a highway.

The video, circulating on social media Friday and geolocated by NBC News, doesn’t show a beleaguered section of the front lines in eastern Ukraine. It is a village in Kursk, across the border in southern Russia.

For days now Vladimir Putin’s forces have struggled to put down an incursion into Russian territory by Ukrainian troops, after a surprise attack that threatened to upend the war’s status quo and open a new front in a daring challenge to the Kremlin.