US President-elect Donald Trump is “strong and unpredictable,” and those qualities can be a decisive factor in his policy approach to Russia’s invasion of Ukraine, according to Ukrainian President Volodymyr Zelenskyy.

However, Zelenskyy said it won’t be possible to end the almost three years of war in one day, as Trump claimed during his election campaign he could do.

“The ‘hot’ stage of the war can end quite quickly, if Trump is strong in his position,” Zelensky said in a Ukrainian television interview late Thursday, referring to fighting on the battlefield.

“I believe (Trump) is strong and unpredictable. I would very much like President Trump’s unpredictability to be directed primarily toward the Russian Federation,” Zelenskyy said.

Trump, who takes office on Jan. 20, hasn’t publicly fleshed out his policy on Ukraine but his previous comments have put a question mark over whether the United States will continue to be Ukraine’s biggest — and most important — military backer.

Zelenskyy is eager to guarantee that Washington’s support keeps coming, and he met with Trump in New York even before last November’s U.S. presidential election.

With the war about to enter its fourth year next month, and with Trump coming to power, the question of how and when Europe’s biggest conflict since World War II might end has come to the fore.

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Russia controls about one-fifth of Ukraine and last year capitalized on weaknesses in Ukraine’s defenses to slowly advance in eastern areas despite high losses of troops and equipment. The war’s trajectory is not in Ukraine’s favor. The country is short-handed on the front line and needs continued support from its Western partners.

Trump responded favorably to the possibility raised by French President Emmanuel Macron of Western peacekeepers being deployed in Ukraine to oversee an agreement that stops the fighting, Zelenskyy said. He met with Trump and Macron in Paris last month.

“But I raised an issue, saying we didn’t hear what specific countries will join this initiative, and whether the US will be there,” Zelenskyy said.

The Ukrainian leader is determined for his country to become a NATO member. The alliance’s 32 member countries say Ukraine will join one day, but not until the war ends.

“The deployment of European troops (to keep the peace in Ukraine) should not rule out Ukraine’s future in NATO,” Zelenskyy said in the television interview.

Zelenskyy described the incursion by Ukrainian forces into Russia’s Kursk border region as a “very strong trump card” in any future peace negotiations.

In a bid to counter glum news from the front line, Ukraine seized part of Kursk last August in what was the first occupation of Russian territory since World War II.

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But the incursion didn’t significantly change the dynamic of the war, and military analysts say Ukraine has lost some 40% of the land it initially captured.

Nevertheless, Zelenskyy said the achievement impressed countries in Asia, South America and Africa and tarnished Russia’s military reputation.