U.S. administration officials signaled Monday a peace deal between Russia and Ukraine may be closer than ever.

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

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

Ukraine has relinquished its ambition of joining the NATO military alliance in exchange for Western security guarantees as a compromise to end the war with Russia, President Volodymyr Zelenskyy said ahead of talks with U.S. envoys in Berlin.

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.

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.

Sergey Ryabkov told ABC News Moscow cannot compromise on key territories.

The Baltic states jointly announced new fortifications on their borders with Russia nearly two years ago.

NATO considers 'more aggressive' stance against Russia's hybrid warfare, including pre-emptive cyber operations, as tensions escalate over sabotage.

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

Ukrainian President Volodymyr Zelenskyy on Sunday voiced readiness to drop his country's bid to join NATO in exchange for Western security guarantees, but rejected the U.S. push for ceding territory to Russia as he held talks with U.