The Baltic countries are registering a dramatic increase in Russian military provocations, rattling nerves in a region which fears it could be the next frontier after Ukraine in Moscow’s quest at asserting its regional power.

Nato fighters policing Baltic airspace were scrambled 68 times along Lithuania’s borders this year, by far the highest count in more than 10 years. Latvia registered 150 “close incidents”, cases where Russian aircraft were found approaching and observed for risky behaviour. Estonia said its sovereign airspace had been violated by Russian aircraft five times this year, nearing the total count of seven over the previous eight years.

Finland has had five violations of its airspace this year against an annual average of one to two in the previous decade, while Sweden last week suffered what Carl Bildt called the “most serious airspace incursion” in his eight years as foreign minister.