LONDON — The European Union and the U.K. will take part in high-level talks on Donald Trump’s peace plan for Ukraine starting Sunday, in a significant breakthrough for Brussels and London, which had been shut out of the process until now.

Top security officials from France and Germany will also attend the negotiations in Switzerland, a senior European official told POLITICO, as Ukraine’s allies seek to re-write Trump’s proposal which they fear would favor Russia.

The fact that the Europeans will get seats at the negotiating table will be welcomed in Kyiv, Brussels and beyond, after Ukraine’s allies voiced their concern at being excluded from Trump’s most recent initiative.

The talks will be held at the level of national security advisers, while Bjoern Seibert, the head of cabinet for European Commission President Ursula von der Leyen, is expected to represent the EU.