Dany Guillaume, director of NATO tactics, told CNN about this.
This information is reportedly confirmed by data collected by NATO reconnaissance aircraft on the border between Poland and Ukraine.
Guillaume said that the day before, the 2nd NATO flying squadron spotted at least 12 Russian aircraft at airfields in Belarus. A few hours later, at least nine of them invaded Ukrainian airspace.
According to him, on one day last week, NATO forces spotted about 20 Russian aircraft heading to Kyiv from Belarus.