Small bands of Russian soldiers thrust deeper into eastern Ukraine on Tuesday before a summit between Russian President Vladimir Putin and US President Donald Trump, which European leaders fear could end in peace terms imposed on an unlawfully shrunken Ukraine.

In one of the most extensive incursions so far this year, Russian troops advanced near the coal-mining town of Dobropillia, part of Putin’s campaign to take full control of Ukraine’s Donetsk region. Ukraine’s military dispatched reserve troops, saying they were in difficult combat against Russian soldiers.

Trump has said any peace deal would involve “some swapping of territories to the betterment of both” Russia and Ukraine, which has depended on the US as its main arms supplier.

But because all the areas being contested lie within Ukraine, President Volodymyr Zelenskiy and his European Union allies fear that he will face pressure to give up far more than Russia does.

In the first US-Russia summit since 2021, Putin and Trump will meet on Friday at Elmendorf Air Force Base in Anchorage, Alaska, two White House officials said.

Trump’s administration on Tuesday tempered expectations for major progress toward a ceasefire, calling the summit a “listening exercise.”

Along that line, US Secretary of State Marco Rubio said the president wanted to size up Putin directly.

“The president feels like, look, I’ve got to look at this guy across the table. I need to see him face to face. I need to hear him one on one. I need to make an assessment by looking at him,” Rubio told WABC radio in New York on Tuesday.

Zelenskiy and most of his European counterparts have said a lasting peace cannot be secured without Ukraine at the negotiating table, and a deal must comply with international law, Ukraine’s sovereignty and its territorial integrity.

They will hold a virtual meeting with Trump on Wednesday to underscore those concerns before the Putin summit.

“Substantive and productive talks about us without us will not work,” Zelenskiy said in an interview on Tuesday with NewsNation. “Just as I cannot say anything about another state or make decisions for it.”

Zelenskiy has said Russia must agree to a ceasefire before territorial issues are discussed. He would reject any Russian proposal that Ukraine pull its troops from the eastern Donbas region and cede its defensive lines.

Asked why Zelenskiy was not joining the US and Russian leaders at the Alaska summit, White House spokeswoman Karoline Leavitt told reporters the bilateral meeting had been proposed by Putin, and Trump accepted to get a “better understanding” of “how we can hopefully bring this war to an end.”

Trump is open to a trilateral meeting with Putin and Zelenskiy later, Leavitt said.

Russia advances in Eastern Ukraine

Sergei Markov, a former Kremlin adviser, suggested Russian advances could increase pressure on Ukraine to yield territory under any deal. “This breakthrough is like a gift to Putin and Trump during the negotiations,” he said.

Despite a troop shortage, Ukraine’s military said it had retaken two villages in the eastern region of Sumy on Monday, part of a small reversal in more than a year of slow, attritional Russian gains in the southeast.

Russia, which launched its full-scale invasion of Ukraine in February 2022, has mounted a new offensive this year in Sumy after Putin demanded a “buffer zone” there.

Ukraine and its European allies fear that Trump, keen to claim credit for making peace and seal new business deals with Russia’s government, will end up rewarding Putin for 11 years of efforts to seize Ukrainian territory, the last three in open warfare.

European leaders have said Ukraine must be capable of defending itself if peace and security are to be guaranteed on the continent, and that they are ready to contribute further.

“Ukraine cannot lose this war and nobody has the right to pressure Ukraine into making territorial or other concessions, or making decisions that smack of capitulation,” Polish Prime Minister Donald Tusk said at a government meeting. “I hope we can convince President Trump about the European position.”

Zelenskiy has said he and European leaders “all support President Trump’s determination.”

Hungarian Prime Minister Viktor Orban, Putin’s principal ally in Europe, was the only leader not to join the EU’s statement of unity. He mocked his counterparts as “sidelined” and said Russia had already defeated Ukraine.

“The Ukrainians have lost the war. Russia has won this war,” Orban told the “Patriot” YouTube channel in an interview.

Trump had been recently hardening his stance towards Russia, agreeing to send more US weapons to Ukraine and threatening hefty trade tariffs on buyers of Russian oil in an ultimatum that has now lapsed.