Former Swedish Foreign Minister Tobias Billström said after the Ukraine war, Europe must be ready for further Russian aggression.

Russian could attack Nato within five years, Mark Rutte said, warning allies to start ramping up preparations "now".

MOSCOW, Dec 14 (Reuters) - The Kremlin said on Sunday that NATO Secretary General Mark Rutte's remarks about preparing for war with Russia were irresponsible and showed that he did not really understand the devastation wrought by World War Two.

Russia's growing aggression prompts NATO warning as recent railway blast in Poland and airspace violations signal escalating security threats across Europe.

NATO Secretary General Mark Rutte warned Thursday that members of the alliance could be “Russia’s next target,” calling for a rapid rise in defense spending to prevent a war similar to those seen by past generations.

Jets and air defense systems were involved in the response, Warsaw said.

German Foreign Minister Johann Wadephul warns that intelligence shows Russia may attack NATO by 2029, citing Moscow's military buildup and economic shift toward war.

Secretary-General Mark Rutte chastised some allies for moving too slowly when it comes to ramping up defense spending.

In a speech in Berlin, Rutte said too many allies of the military alliance did not feel the urgency of Russia's threat in Europe and that they must rapidly increase defence spending and production to prevent a war on the scale of that seen by past generations.

As Georgia balances its aspirations to join NATO against mounting pressure from the Russian Federation, a new security partnership is taking shape in the South Caucasus.