.Putin contacts cross-border attack in Kursk area a 'provocation' The Washington PostRussia states Ukrainian troops crossed right into its area and also launched 'substantial assault' CNNHow deep into Russian region has Ukraine's surprise August attack arrived at? MeduzaUkraine Launches Rare Cross-Border Ground Attack Into Russia The New York City TimesRussia: State of emergency in Kursk in the middle of incursion DW (English).