"The French presidential adviser will travel to Geneva tomorrow with colleagues from the E3 (Britain, France and Germany)," one of these sources said on the sidelines of the South African summit on Saturday.

"The talks will take place between the US, the E3 and the Ukrainians," another source said.

On the US side, the peace plan will be discussed by Trump's special envoy Steve Witkoff and Secretary of State Marco Rubio, a US official said.

The official also said that US Army Secretary Daniel Driscoll, who met with Ukrainian President Volodymyr Zelensky in Kiev on Thursday, had already arrived in the Swiss city on Saturday.

Washington has reportedly proposed a plan to end the war in Ukraine, which appears to be based largely on Russian demands. It includes not only the retention of the occupied territories under Russian control, but also Ukraine's commitment not to join NATO, not to expand the alliance, and Russia's return to the G8, according to a draft of the plan obtained by AFP.