German Chancellor Friedrich Merz has invited Ukraine's President Volodymyr Zelensky as well as the French, British and other European leaders and the heads of the EU and NATO to an afternoon video conference.

They are then expected to talk to Trump and Vice President JD Vance in a second round of the conference call.

The Trump-Putin meeting on Friday -- their first since Russia launched its full-scale invasion of Ukraine over three years ago -- is so far planned to go ahead without Zelensky.

This has fuelled fears Kyiv could be forced into painful concessions, including over land.

EU leaders stressed on Tuesday "the inherent right of Ukraine to choose its own destiny", adding that "international borders must not be changed by force".

Zelensky, speaking to reporters Tuesday, ruled out withdrawing troops from the Donbas region which Moscow claims.

Merz's office said the conference call would discuss "further options to exert pressure on Russia" and "preparation of possible peace negotiations and related issues of territorial claims and security".

The talks would include leaders from "Finland, France, the UK, Italy, Poland, Ukraine, the heads of the European Commission and Council, the secretary general of NATO, as well as the US president and his deputy", Berlin said on Monday.

British Prime Minister Keir Starmer, French President Emmanuel Macron and Merz are then also set to hold a round of talks of the so-called Coalition of the Willing of Ukraine's military backers.

- 'Difficult' battles -

Trump on Monday played down the possibility of a breakthrough in Alaska but said he expected "constructive conversations" with Putin.

"This is really a feel-out meeting a little bit," Trump said at the White House, but he also added that eventually "there'll be some swapping, there'll be some changes in land".

Russia, as a prerequisite to a peace settlement, has demanded Kyiv pull its forces out of several regions claimed by Moscow, commit to being a neutral state, shun US and EU military support and be excluded from joining NATO.

Ukraine has said it would never recognise Russian control over its sovereign territory, though it acknowledged that getting land captured by Russia back would have to come through diplomacy, not on the battlefield.

Ukraine said Tuesday it was engaged in "difficult" battles with Russian forces after Moscow had made rapid advances in a narrow but important section of the front line in the country's east.

Zelensky said on social media that "we see that the Russian army is not preparing to end the war. On the contrary, they are making movements that indicate preparations for new offensive operations."

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