German Chancellor Friedrich Merz suggested on Monday that Ukraine may have to accept that parts of its territory could remain outside Kyiv's control in a future peace deal with Russia, linking such concessions to the country's prospects for joining the European Union.

"At some point, Ukraine will sign a ceasefire agreement; at some point, hopefully, a peace treaty with Russia. Then it may be that part of Ukraine's territory is no longer Ukrainian," Merz told students at the Carolus-Magnus-Gymnasium in Marsberg, a town in North Rhine-Westphalia, on Monday.

"If President (Volodymyr) Zelensky wants to communicate this to his own population and gain a majority for it, and he needs to hold a referendum on it, then he must at the same time tell the people: 'I have opened the way to Europe for you'," Merz added.

Kyiv's EU accession progress had been blocked by Hungary's nationalist premier Viktor Orban, but his defeat in elections earlier this month raised hopes it can move to the next step. Ukraine currently has the status of an official EU candidate.