More from the cited article...

... It's worth noting that, around the same time Su-27s were bombing Russian positions in Kursk, other Ukrainian jets were bombing three Russian-held towns in Kharkiv Oblast around 100 miles southeast of the Kursk salient, according to CDS.

Still, it's remarkable that, despite a serious disadvantage in jets, bombs and other heavy weaponry, Ukraine hasn't just invaded Russia"the invasion shows no sign of slowing. ...