Who is actually jamming aircrafts’ general practitioner in the Baltic?

.ON APRIL 29TH Finnair, Finland’s national airline company, pointed out that it will put on hold flights to the asian Estonian city of Tartu for a month. Recently 2 aircrafts were actually obliged to reverse after their general practitioner signs were actually interfered with. General practitioner jamming has enhanced greatly in the Baltic region over the past pair of years.

That is behind it as well as exactly how dangerous could it be?