Volodymyr Zelenskyy has said the operation in Kursk aims to create a buffer zone.
It's the first time the Ukrainian president has clearly stated the aim of the incursion into Russian territory, which was launched on 6 August.
He has previously said the operation is to protect communities in the bordering Sumy region from constant shelling.
"It is now our primary task in defensive operations overall - to destroy as much Russian war potential as possible and conduct maximum counteroffensive actions," he has just said in his nightly address.
