NATO Secretary-General Jens Stoltenberg warned today that Russian President Vladimir Putin will wage war elsewhere if Russia defeats Ukraine.

“If Putin wins in Ukraine, there is real risk that his aggression will not end there,” Stoltenberg told reporters during a meeting with Slovakia’s Prime Minister Robert Fico. “Our support is not charity. It is an investment in our security.”

Fico, who won September’s election, is skeptical of aiding Ukraine and has ended military deliveries to Kyiv.

But Stoltenberg wants the alliance to hold firm against Russia.

“The only way to reach a just and lasting solution is to convince President Putin that they will not win on the battlefield.And the only way to ensure that President Putin realizes that he is not winning on the battlefield is to continue to support Ukraine,” the NATO chief said.

His comments came on the same day the Russian leader made clear he has no intention of backing down in his war against Ukraine.