Germany’s Chancellor Friedrich Merz compared Russian President Vladimir Putin to Adolf Hitler in a speech Saturday evening, warning that the Kremlin leader’s ambitions won’t stop with Ukraine.

“Just as the Sudetenland was not enough in 1938, Putin will not stop,” Merz said, referring to a part of Czechoslovakia that the Allies ceded to the Nazi leader with an agreement. Hitler continued his expansion into Europe after that.

“If Ukraine falls, he won’t stop there,” Merz said, referring to Putin.

German, British and French officials are set to meet in Berlin this weekend to discuss proposals to end the war in Ukraine. U.S. envoy Steve Witkoff is also expected to meet with Ukraine’s President Volodymyr Zelenskyy.

The talks are in preparation for a planned summit of leaders including Merz, Britain’s Keir Starmer, France’s Emmanuel Macron and Zelenskyy on Monday over stopping Russia’s aggression against Ukraine.

A U.S.-backed 20-point peace plan is in the works, which includes territorial concessions on Ukraine’s part. Under one proposal being discussed, the Donbas region would be made into a free-trade zone were American companies can freely operate.

Merz was speaking at a party conference of the Christian Social Union of Bavaria, which is closely aligned with his own party, the Christian Democrats.