Ukraine won't surrender land to Russia to buy peace, President Volodymyr Zelensky warned Saturday, after Washington and Moscow agreed to hold a summit in a bid to end the war.

Presidents Vladimir Putin and Donald Trump will meet in the US state of Alaska next Friday, to try to resolve the three-year conflict, despite warnings from Ukraine and Europe that Kyiv must be part of negotiations. 

Announcing the summit on Friday, Trump said that "there'll be some swapping of territories to the betterment of both" sides, without providing further details.

"Ukrainians will not give their land to the occupier," Zelensky said on social media hours later.

"Any decisions against us, any decisions without Ukraine, are also decisions against peace. They will achieve nothing," he said, adding that the war "cannot be ended without us, without Ukraine".

Zelensky also urged Ukraine's allies to take "clear steps" towards achieving a sustainable peace, during a call with Britain's Prime Minister Keir Starmer.

National security advisors from Kyiv's allies — including the United States, EU nations and the UK — were gathering in Britain on Saturday to align their views ahead of the Putin-Trump summit.

French President Emmanuel Macron, following phone calls with Zelensky, Starmer and German Chancellor Friedrich Merz, said "the future of Ukraine cannot be decided without Ukrainians" and that Europe also had to be involved in the negotiations.

Later Saturday, in his evening address, Zelensky added: "There must be an honest end to this war, and it is up to Russia to end the war it started."

A 'dignified peace'

Three rounds of talks between Russia and Ukraine this year have failed to bear fruit, and it remains unclear whether a summit could bring peace any closer as the warring sides' positions are still far apart.

Tens of thousands of people have been killed since Russia launched its full-scale invasion of Ukraine in February 2022, with millions forced to flee their homes.

Putin has resisted multiple calls from the United States, Europe and Kyiv for a ceasefire.

Putin, a former KGB officer in power in Russia for over 25 years, has ruled out holding talks with Zelensky at this stage.

Ukraine's leader has been pushing for a three-way summit and has frequently said meeting Putin is the only way to make progress towards peace.

Far from the war

The summit in Alaska, the far-north territory which Russia sold to the United States in 1867, would be the first between sitting US and Russian presidents since Joe Biden met Putin in Geneva in June 2021.

Nine months later, Moscow sent troops into Ukraine.

Zelensky said of the location that it was "very far away from this war, which is raging on our land, against our people". 

The Kremlin said the choice was "logical" because the state close to the Arctic is on the border between the two countries, and this is where their "economic interests intersect".

Moscow has also invited Trump to pay a reciprocal visit to Russia later. 

Trump and Putin last sat together in 2019 at a G20 summit meeting in Japan during Trump's first term. They have spoken by telephone several times since January with Trump trying to broker peace in Ukraine without making a breakthrough.

On Friday, Putin held a round of calls with allies, including Brazil, China and India, in a diplomatic flurry ahead of the Alaska summit. 

In a 40-minute phone conversation Saturday between Putin and President Luiz Inacio Lula da Silva, the Brazilian leader reiterated his support for dialogue "and the pursuit of a peaceful solution", his office said.

The US president had earlier imposed an additional tariff on India for buying Russia's oil in a bid to nudge Moscow into talks. He also threatened to impose a similar tax on China, but so far has refrained from doing so.  

Fighting goes on

Russia and Ukraine continued pouring dozens of drones onto each other's positions in an exchange of attacks in the early hours of Saturday. 

A bus carrying civilians was hit in Ukraine's frontline city of Kherson, killing two people and wounding 16. 

The Russian army claimed to have taken Yablonovka, another village in the Donetsk region, the site of the most intense fighting in the east and one of the five regions Putin says is part of Russia. 

Four people were killed as of Saturday morning in Donetsk after Russian shelling, Ukrainian authorities said. 

In 2022, the Kremlin announced the annexation of four Ukrainian regions — Donetsk, Lugansk, Zaporizhzhia and Kherson — despite not having full control over them. 

Russia had previously annexed the Crimean peninsula from Ukraine in 2014.

As a prerequisite to any peace settlement, Moscow demanded Kyiv pull its forces out of the regions and commit to being a neutral state, shun Western military support and be excluded from joining NATO.

Kyiv 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.