
NATO  warplanes have had to scramble 400 times this year in response to an  increase in Russian air activity around Europe not seen since the Cold  War, the alliance’s chief said on Thursday.
 
 North Atlantic Treaty Organisation members have sought to fill  gaps in the alliance’s land, air and sea defences since Russia annexed  Crimea and backed a secessionist movement in the eastern part of  Ukraine.
 
 Speaking to U.S., German and Estonian troops at a newly expanded  and renovated air base in western Estonia, which once housed a Soviet  military installation, Secretary-General Jens Stoltenberg said the  problem was not just where the Russians are flying but that they are not  turning on their transponders or communicating.
 
 He said the flights – which have risen 50 percent over the last year – posed a risk to commercial air traffic.
 
 “This pattern is risky and unjustified, so NATO remains vigilant.  We are here and we are ready to defend all our allies against any  threats,” Stoltenberg said in a speech after meeting Estonian Prime  Minister Taavi Roivas.
 
 “It is a pattern which we have not seen for many years and it is a  pattern that reminds us of the way they conducted these kind of  military air activities back in the time of the Cold War.”
 
 Vice Admiral Peter Hudson, commander of NATO’s Allied Maritime  Command, said Russia was using its military forces in a “much more  assertive manner”, which included more Russian naval activity in the  Baltic region.
 
 “From a NATO perspective, we are going about our legitimate  business in international waters working with our allies. They are  occasionally interfering, occasionally operating as a nuisance,” Hudson  told Reuters in London.
 
 “Safety has not been breached, but it is just a style of behaviour  which we have not seen for 25 years, since the end of the Cold War,” he  said.
 
 Stoltenberg said most of the Russian flights were close to NATO air space, with “very limited numbers of violations”.
 
 NATO allies remain concerned that France could still decide to  sell an advanced military helicopter carrier to Russia, Stoltenberg  said, but added that this was not a decision that NATO had any authority  over.