The United States’ policy shift on Ukraine should serve as a wake-up call for Europe, Greece’s Prime Minister Kyriakos Mitsotakis said on Wednesday.

Mitsotakis warned the continent’s leaders against slowing down on geopolitical and economic issues, which he opined had been the case in the recent past.

The Greek PM’s advice came on the back of President Donald Trump’s strong criticism of President Volodymyr Zelenskyy’s handling of the war with Russia.

Trump knocks Zelenskyy over Russia-Ukraine war

In remarks at Mar-a-Lago on Tuesday, Trump questioned the use of funds Ukraine had received from the United States and the North Atlantic Treaty Organization (NATO).

Trump said his country had spent more than $300 billion in aid, while Europe’s transnational military alliance had expended only about a third of that figure.

Speaking at a business conference in Thessaloniki, Mitsotakis urged Europe to “wake up from the geopolitical and economic lethargy into which it has unfortunately fallen for some time.”

The PM added that the “different view of things from the United States” now obliges nations in the region to face the truth, move at a very high speed, and implement decisions on deliberations.

Since returning to the White House, Trump has repeatedly stated that Europe would have to step up its financial support, saying they had more at stake in the Russia-Ukraine conflict than America.

Though the U.S. has initiated moves to end the three-year-long battle, with special envoy Keith Kellogg leading the talks, the president has publicly communicated his decision to defund Ukraine.