The Polish prime minister, Donald Tusk, says Europe is entering a “prewar” era, cautioning that the continent is not ready and urging European countries to step up defence investment.

In an interview with a group of European newspapers reported by the BBC, Tusk said: “I don’t want to scare anyone, but war is no longer a concept from the past. It’s real and it started over two years ago.”

Tusk’s comments came days after a Russian missile briefly breached Polish airspace during a major attack on Ukraine, prompting Warsaw to put its forces on heightened readiness. Ukrainian officials have said large-scale Russian missile and drone attacks had targeted energy infrastructure.

Tusk has been using his platform to try to add a sense of urgency to Europe’s debates about defence and aid to Ukraine, amid fears about the future of American assistance and concerns about defence industrial capacity.