TALLIN, November 20. /TASS/ . NATO is concerned over increased Russian air activity over Europe and is ready to defend its allies against any threats, NATO Secretary General Jens Stoltenberg said during his visit to Estonia.

"Russian air activity has increased all over Europe,” Stoltenberg said. The official said the pattern is risky and noted that NATO remains vigilant.

"We are ready to defend all Allies against any threat," he said. 

Vladimir Putin on NATO’s expansion

Russian President Vladimir Putin said in an interview with German TV channel ARD said the NATO experienced two considerable waves of its expansion significantly changing the geopolitical situation.

“We have witnessed two waves of NATO expansion since 2001,” Putin said. “If I remember correctly, seven countries - Slovenia, Slovakia, Bulgaria, Romania and three Baltic States, Estonia, Latvia and Lithuania - joined NATO in 2004. Two more countries joined in 2009. Those were significant geopolitical game changers.

“Furthermore, the number of military bases is growing,” he said. “Does Russia have military bases around the world? NATO and the United States have military bases scattered all over the globe, including in areas close to our borders, and their number is growing.”