Guido Crosetto, a co-founder of right-wing premier Giorgia Meloni's ruling party, also said European countries should not ignore the importance of Russia, as well as Ukraine, moving away from a war economy to normal activity once the conflict ends.

The United States has put forward an updated version of its plan to halt the deadliest fighting in Europe since World War II after the initial blueprint alarmed both Kyiv and European allies who feared it reflected maximalist Russian demands.

Moscow has said that the ongoing talks on the plan were "serious" but European leaders have expressed scepticism, with French President Emmanuel Macron saying there was "clearly no Russian willingness" to agree a ceasefire.

"I don't know what Putin has in mind," Crosetto told reporters at the Italian embassy in Paris after meeting his French counterpart Catherine Vautrin.

"We hope that this time Russia will truly want to sit down at the table and negotiate. Looking at what's happening, I'm not optimistic," he said, noting that Russia was still recruiting troops and boosting defence investment.

But he added: "Russia is paying for this war domestically, with a decline in its GDP, its wealth.

"We'll see in the coming weeks -- it won't take long to understand -- whether Putin has a real intention" to make peace, he said.

He also cautioned that Europe, as well as helping Ukraine rebuild, should not turn a blind eye to Russia's postwar transition or else risk a resumption of conflict.

"Remember what happened in Europe when, after World War I, veterans returned home and created the conditions for the rise of Nazism and Fascism," he said, referring to the rise of dictators Adolf Hitler and Benito Mussolini.

"Think of the two and a half million Russians who, after earning three times the normal Russian wage, will return home and have to find work. What instability this will create in Russia!"

Only by creating the conditions in Ukraine and Russia "so that the war economy can be dismantled and replaced by an economy of peace and growth" can a path to "peace be created that can develop over ten years", he said.