European leaders including from Germany, France and Britain will join Volodymyr Zelenskiy to meet Donald Trump in Washington, they said on Sunday, seeking to shore up his position as the US president presses Ukraine to accept a quick peace deal.

Trump is leaning on Zelenskiy to strike an agreement after he met Kremlin Chief Vladimir Putin in Alaska, and on Sunday promised “big progress on Russia” in a social media post without specifying what this might be.

US Secretary of State Marco Rubio said Trump had seen enough to justify meeting Zelenskiy and the Europeans on Monday but added that both Russia and Ukraine would need to make concessions.

German Chancellor Friedrich Merz, French President Emmanuel Macron and British Prime Minister Keir Starmer were hosting a meeting of allies on Sunday to bolster Zelenskiy’s position, hoping in particular to lock down robust security guarantees for Ukraine that would include a US role.

According to sources, the US and Russian leaders discussed at their summit on Friday proposals for Russia to relinquish tiny pockets of occupied Ukraine in exchange for Ukraine ceding a swathe of fortified land in the east and freezing the front lines elsewhere.

At face value, some of Putin’s demands would be hugely difficult for Ukraine to accept, setting the stage for potentially fraught talks about ending Europe’s deadliest war in 80 years, which has dragged on for three-and-a-half years and killed or wounded more than one million people.

European allies are keen to help Zelenskiy avoid a repeat of his last Oval Office meeting, in February. That went disastrously, with Trump and Vice President JD Vance giving the Ukrainian leader a public dressing-down, accusing him of being ungrateful and disrespectful.

European Commission President Ursula von der Leyen will also travel to Washington, as will Finland’s President Alexander Stubb, whose access to Trump included rounds of golf in Florida earlier this year, and Italian Prime Minister Giorgia Meloni, who is an admirer of many of Trump’s policies.

His comments follow the summit in Alaska, where Vladimir Putin was reported to have demanded more Ukrainian land.

“It’s important that Washington is with us,” Zelenskiy said alongside von der Leyen on a visit to Brussels, saying that the current frontlines in the war should be the basis for peace talks. “Putin does not want to stop the killing but he must do it.”

Setting out redlines, von der Leyen said Ukraine’s allies wanted robust security guarantees for Ukraine, no limits to Ukraine’s armed forces and a seat at the table for Ukraine to discuss its territory.

“As I’ve often said, Ukraine must become a steel porcupine, indigestible for potential invaders,” she said.

Macron, Merz and Starmer were hosting a virtual meeting of the “coalition of the w” – a grouping of allies of Kyiv – on Sunday, a discussion that included Zelenskiy.

European powers want to help set up a trilateral meeting between Trump, Putin and Zelenskiy to make sure Ukraine has a seat at the table to shape its future.

They also want security guarantees for Ukraine with US involvement and the ability to crank up pressure on Moscow if needed.

Speaking to CBS on Sunday, Rubio said both Ukraine and Russia would have to make concessions to reach a peace deal and that security guarantees for Ukraine would be discussed on Monday. He also said there would have to be additional consequences for Russia if no deal was reached.

“I’m not saying we’re on the verge of a peace deal but I am saying that we saw movement, enough movement to justify a follow up meeting with Zelenskiy and the Europeans, enough movement for us to dedicate even more time to this,” Rubio said.

However, he said the US may not be able to create a scenario to end the war.

“If peace is not going to be possible here and this is just going to continue on as a war, people will continue to die by the thousands … we may unfortunately wind up there, but we don’t want to wind up there,” Rubio said in an interview with “Face the Nation.”

For his part, Putin briefed his close ally, Belarusian President Alexander Lukashenko, about the Alaska talks, and also spoke with Kazakhstan’s President Kassym-Jomart Tokayev. Trump said on Friday that Ukraine should make a deal to end the war because “Russia is a very big power, and they’re not”.

After the Alaska summit, Trump phoned Zelenskiy and told him that the Kremlin chief had offered to freeze most front lines if Ukraine ceded all of Donetsk, the industrial region that is one of Moscow’s main targets, a source familiar with the matter said.

Zelenskiy rejected the demand. Russia already controls a fifth of Ukraine, including about three-quarters of Donetsk province, which it first entered in 2014.

Trump also said he agreed with Putin that a peace deal should be sought without the prior ceasefire that Ukraine and its European allies have called for. That was a reversal of his position before the summit, when he said he would not be happy unless a ceasefire was agreed on.

• Reuters report