On 6 August Ukrainian infantry and armoured units crossed the frontier into the Kursk Oblast and began the first substantial offensive into Russia by a foreign power since the Second World War. Ukrainian Armed Forces (UAF) seized operational surprise, a rare occurrence in a war characterised for the past year by grinding position warfare where movement has been difficult and very costly. In 10 days Ukrainian forces have advanced more than 20 miles and control nearly 450 square miles of Russian territory.

More than 80 settlements have fallen into Ukrainian hands and Russia has been forced to evacuate as many as 150,000 civilians. What is being called Ukraine’s Kursk incursion is a stunning turn of events in a conflict that has been until now fought entirely on Ukrainian soil. But this undeniable success is a high risk operation.

Why have Ukraine’s leadership taken this gamble? What are the aims of this operation? How could it affect the course of the war? The Ukrainian incursion likely has three chief objectives. The first is operational: to draw Russian armed strength northward in order to relieve pressure on the Kharkiv and Donbas regions to the east and south, where fighting has been very heavy and the UAF have been hard pressed to hold ground. So far this effort has achieved limited success.

Russia has reportedly begun moving units northward from Zaporizhzhia and Dnipro in the south toward the Kursk region. But Russia’s military leadership has resisted withdrawing he.