Russia analyst Tatiana Stanovaya said Mr Putin’s plan is a set of “maximalist” demands that offer no concessions, timed to devalue the peace conference ahead of it beginning.
Mr Zelensky will be attending Saturday’s summit near Lake Lucerne, where he will hope to show he still enjoys wide international support.
The Swiss government has said the aim of the summit is “to provide a forum where world leaders discuss paths towards a just and lasting peace in Ukraine, based on international law and the UN Charter”.
Other attendees will include US Vice-President Kamala Harris, French President Emmanuel Macron, German Chancellor Olaf Scholz, Italian Prime Minister Giorgia Meloni and European Commission President Ursula von der Leyen.
Russia was not invited and China has said it will not attend without Russia’s presence.
The peace summit comes after G7 leaders agreed to use interest from frozen Russian assets to help Ukraine fight invading Russian forces.
Some $325bn (£256bn) worth of assets were frozen by G7 countries, alongside the EU, following Russia’s full-scale invasion of Ukraine in February 2022. The pot of assets is generating about $3bn a year in interest.
Under the G7 plan, that $3bn will be used to pay off the annual interest on a $50bn loan for the Ukrainians, taken out on the international markets.
The money is not expected to arrive until the end of the year but is seen as a longer-term solution to support Ukraine’s war effort and economy.
On the sidelines of the G7 summit, the US and Ukraine also signed a 10-year bilateral security deal, hailed by Kyiv as “historic”.
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