Asked if US President Donald Trump would stick to the points discussed in Berlin in the continuing negotiation process with Russia, Hardt said: "I have no doubt that we can trust the US president and what he said to the heads of state [on Monday] in the chancellery via video.

"[Steve] Witkoff and [Jared] Kushner, his two ambassadors on that question, [are] also strongly committed to that plan. Therefore, I'm optimistic that the alliance between the US, Ukraine and the European states is sustainable."

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