The thinking behind Ukraine's shock invasion of Russian border regions over the last two weeks has been the subject of intense speculation since it began on 6 August.
An aide to Volodymyr Zelenskyy has now offered a possible insight into Kyiv's plan, saying the incursion in Kursk was needed to convince Russia to start "fair" talks on a peace settlement.
Presidential adviser Mykhailo Podolyak said Kyiv needed to "inflict significant tactical defeats on Russia".
"In the Kursk region, we can clearly see how the military tool is being used objectively to persuade [Russia] to enter a fair negotiation process," he wrote in a post to X.
Mr Podolyak said Ukraine was "not interested" in occupying Russian territory and was waging an "exclusively defensive war".
of course just one mans opinion ....certainly a bargaining chip for Ukraine