A U.S. proposal to end the war in Ukraine has opened some disagreement with key European allies, with Paris, Berlin and Helsinki signaling they will not be sidelined during talks in Geneva.

A senior European diplomat told Fox News Digital that Europe would not accept a U.S.-driven agreement without full European involvement. "No negotiations about Ukraine without Ukrainians. No negotiations about Europe’s security without Europeans," the diplomat said.

Some of the European concerns came a day after Secretary of State Marco Rubio said on Sunday that the U.S. and Ukraine made "substantial" headway on an "updated and refined peace framework." He called it "the most productive day we have had," acknowledged unresolved issues, and said matters involving the EU and NATO would proceed on a "separate track." Negotiators from the U.S., Ukraine and major European states are expected to continue discussions throughout the week.

The European official called the American plan "a basis that requires further work," adding that "the first of these conditions must be the implementation of a ceasefire along the line of contact." According to the diplomat, France and the United Kingdom will convene a Coalition of Volunteers meeting on Tuesday to coordinate Europe’s position.

German Chancellor Friedrich Merz warned at the Group of 20 summit in South Africa over the weekend that Europe cannot be cut out of any settlement. "Wars cannot be ended by major powers over the heads of the countries affected," he said, adding, "We are still quite a way from a good outcome for everyone."

French President Emmanuel Macron echoed those concerns on the sidelines of the summit, saying the U.S. plan "has not been negotiated with the Europeans," even though it contains "many provisions that concern Europeans directly." He pointed to proposed limits on Ukraine’s military capacity, calling them "limitations on the size of the Ukrainian army — in other words, on its own sovereignty."

"It is positive in the sense that it proposes a path to peace and acknowledges important elements regarding sovereignty, security guarantees, and other issues. But it is only a basis for work that needs to resume, just as we did last summer, because this plan has not been negotiated with the Europeans," Macron told reporters.

Finland’s President Alexander Stubb Ukrainian President Volodymyr Zelenskyy reinforced Kyiv’s red lines in an address to Sweden’s parliament on Monday, "The aggressor must pay fully for the war he started," rejecting territorial concessions. "Putin wants legal recognition for what he has stolen… That is the main problem," Zelenskyy said.

Moscow dismissed emerging European ideas as "not constructive," according to Russian presidential aide Yuri Ushakov, according to Reuters.