President Volodymyr Zelenskyy has ruled out Ukraine ceding land to Russia and demanded his country take part in negotiations in comments made before planned talks between the leaders of Russia and the United States.

In a video shared on social media on Saturday, Zelenskyy said Ukraine was ready for “real decisions” that could bring a “dignified peace” but stressed there could be no violation of the constitution on territorial issues.

“Ukrainians will not gift their land to the occupier,” he said, warning that “decisions without Ukraine” would not bring peace.

“They will not achieve anything. These are stillborn decisions. They are unworkable decisions. And we all need real and genuine peace. Peace that people will respect,” added Zelenskyy, whose country has been fighting off a full-scale Russian invasion since February 2022.

His comments came hours after US President Donald Trump said a peace deal would involve “some swapping of territories” as he announced a meeting on Friday with his Russian counterpart, Vladimir Putin, in the US state of Alaska to discuss the war in Ukraine.

Tens of thousands of people have been killed since Russia launched its invasion of Ukraine, which also forced millions of people to flee their homes.

Three rounds of negotiations between Russia and Ukraine this year have failed to bear fruit, and it remains unclear whether a summit would bring peace any closer.

On Thursday, Putin said he considers a meeting with Zelenskyy possible but the conditions for such negotiations must be right and the prerequisites for this are still far from being met.

The Russian president did not outline his conditions, but previously, the Kremlin has insisted that Ukraine give up the territories Russia occupies, Western nations stop supplying Ukraine with weapons and they exclude Ukraine from membership in the NATO military alliance.

“There has been a lot of speculation over what a ceasefire agreement could look like in which the lines of contact between Russia and Ukraine could be frozen for a number of years,” Al Jazeera’s Osama Bin Javad, reporting from Moscow, said.

“It is also not clear whether the Russian demand that NATO’s ambitions in Ukraine should be forever quashed is actually going to be met.”

Separately on Saturday, Zelenskyy spoke with British Prime Minister Keir Starmer and urged Ukraine’s allies to take “clear steps” towards achieving a sustainable peace.

Zelenskyy said he also shared the same view with Starmer on the danger of Russia’s plan “to reduce everything to discussing the impossible”.

The Ukrainian president also spoke with his French counterpart, Emmanuel Macron. “I am grateful for the support. We exchanged views on the diplomatic situation,” Zelenskyy said on social media, “it is truly important that the Russians do not succeed in deceiving anyone again”.

For his part, Macron said he had also spoken to Starmer and German Chancellor Friedrich Merz and express the European countries’ determination to support Ukraine.

“Ukraine’s future cannot be decided without the Ukrainians, who have been fighting for their freedom and security for over three years now,” he said. “Europeans will also necessarily be part of the solution, as their own security is at stake.”

Meanwhile, national security advisers from Ukrainian allies – including the US, European Union nations and the UK – were gathering in Britain on Saturday to align their views ahead of the Putin-Trump summit.

Ukraine and its European allies have long opposed any agreement that involves ceding occupied territory, but Putin has repeatedly said any deal must require Ukraine to relinquish some of the territories Russia has seized.

Russia declared four Ukrainian regions that it does not fully control – Kherson, Donetsk, Zaporizhia and Luhansk – its territory in 2022 and also claims the Black Sea peninsula of Crimea, which it annexed in 2014.

Putin aide Yuri Ushakov said the talks between the presidents of Russia and the US next week will “focus on discussing options for achieving a long-term peaceful resolution to the Ukrainian crisis”.

“This will evidently be a challenging process, but we will engage in it actively and energetically,” Ushakov said.

The Alaska summit would be the first between sitting US and Russian presidents since Joe Biden met Putin in Geneva in June 2021.

Trump and Putin last sat together in 2019 at a Group of 20 summit in Japan during Trump’s first term. They have spoken by telephone several times since Trump returned to the White House in January.