• NATO Secretary General Mark Rutte said members have to boost spending.
• If not Europeans should "get out your Russian language courses or go to New Zealand," he said.
• The security alliance faces an intensified threat from Russia.

NATO Secretary General Mark Rutte told members of the security alliance to boost defense spending or prepare to learn Russian.

Speaking at the European Parliament in Strasbourg, France, Monday Rutte told European lawmakers that they have to urgently rethink spending priorities to ensure their security.

It was the latest in a string of calls for Europe to rewire their economies to prioritize defense more heavily, as Russia continues its invasion of Ukraine and President-elect Donald Trump maintains his skepticism of the US underwriting European security.

The line was to illustrate what NATO sees as the intensifying threat from Russia and President Vladimir Putin.

"We are safe now, but not in four or five years," he said.

The alternative to higher spending, he said, was to "get out your Russian language courses or go to New Zealand."

"I'm deeply concerned about the security situation in Europe," he said. "We are not at war, but we are not at peace either ... That means we need to invest more in defense and produce more capabilities. This cannot wait. We need to boost the resilience of our societies and critical infrastructure."

European military and security officials have warned that Russia could attack a NATO country next if it defeats Ukraine.

In the wake of the Russian invasion of Ukraine, most members of the security alliance have boosted their military budgets, with 23 of its 32 members now spending 2% of GDP on defense.

The alliance has a 2% GDP defense spending target for members, but for years many lagged well behind this.

President-elect Donald Trump has long berated NATO members for not spending more on their own security — and has called on spending to be raised even further, to 5% of GDP.

The US spends around 3.38% of GDP on defense, and European countries in eastern Europe closer to Russia spend a similar percentage, with Estonia spending 3.43% and Latvia 3.15%.

Poland, which has one of Europe's most powerful militaries and spends 4.1% of GDP on defense, welcomed Trump's 5% spending proposal. Leaders in other countries, including Germany's Chancellor Olaf Scholz, say the target is too high.

Rutte said that, come what may, nations would have to start spending more, with a 3.7% target likely.

During Trump's first term, when he threatened to withdraw from NATO, some European leaders, including France's Emmanuel Macron, said that Europe had to become more self-sufficient in ensuring its security.

NATO members have boosted spending, but the US remains by far the biggest military power of the alliance. Rutte said Monday that Europe would continue to depend on the US for its security.