Europe is sounding the alarm amid growing concern that Russian President Vladimir Putin’s veiled threats against the NATO military alliance could become real.

An increasingly aggressive Putin could attack the NATO military alliance in less than a decade, German Defense Minister Boris Pistorius warned, POLITICO reported in an op-ed.

“We hear threats from the Kremlin almost every day … so we have to take into account that Vladimir Putin may even attack a NATO country one day,” Pistorius told the German magazine Der Tagesspiegel in an interview published on Friday.

While a Russian attack is not likely “for now”, the minister added: “Our experts expect a period of five to eight years in which this could happen.”

After the Kremlin’s widespread invasion of Ukraine, Russia has stepped up its aggressive rhetoric against some of its neighbors, including the Baltic states and Polandwhich are all members of NATO, but also of Moldova, intensifying the concern about the potential risk of a major conflict.

On Wednesday, the chairman of NATO’s military chiefs’ committee, Admiral Rob Bauer, said the military alliance was facing “the most dangerous world in decades” and called for “a warfighting transformation of NATO”.

Earlier this month, Sweden’s commander-in-chief General Micael Bydén similarly called on Swedes to “mentally prepare” for war.

On the same day, Sweden’s Civil Defense Minister Carl-Oskar Bohlin also warned that “a war may be waged in Sweden”.

In his interview with Der Tagesspiegel, Pistorius said the Swedish warnings were “understandable from a Nordic perspective”, adding that Sweden faced “an even more serious situation” given its proximity to Russia. It is also not yet a member of the NATO alliance, awaiting approval from Turkey and Hungary to join.

“But we also have to learn to live with the risk again and prepare, militarily, socially and in terms of civil defence,” Pistorius warned.

Poland, which is spending more than 4% of its GDP on defense this yearis also concerned that the surprise attack on Ukraine in 2022 demonstrates that Russia is unpredictable.

“Russia defies logic. What happened in 2022 seemed impossible. We have to be ready for any scenario,” Defense Minister Władysław Kosiniak-Kamysz said in a televised interview earlier this week.

Late last year, Germany revamped its military and strategic doctrine for the first time since 2011, with the aim of putting the Bundeswehr on military readiness for war.

“War is back in Europe. Germany and its allies must once again face a military threat. The international order is under attack in Europe and around the world. We live at a turning point,” said the first paragraph of the new doctrine.