President Donald Trump said on Thursday that a minerals deal with Ukraine is the security guarantee Kyiv needs against Russia, brushing aside a plea from British Prime Minister Keir Starmer for a commitment of more U.S. military support.

Starmer, who was meeting Trump at the White House for the first time since the U.S. leader started his second term, turned on the charm, saying peace in Ukraine had only become possible because of Trump.

But underlying differences between the allies remained on the table for the private conversation that followed, including transatlantic frictions over U.S.-Russia talks over the Ukraine war.

Before the meeting, Starmer had argued that there could be no long-term peace in Ukraine without firm U.S. security guarantees - an argument Trump all but dismissed.

"We are a backstop because we'll be over there, we'll be working," as a result of the economic partnership, Trump said. "We're going to have a lot of people over there."

Starmer is the latest European leader to meet Trump after French President Emmanuel Macron came to the White House on Monday for a friendly encounter that nonetheless displayed stark differences about Russia's war with Ukraine and the U.S. push for a quick ceasefire.

Trump expressed optimism that a ceasefire deal in Ukraine could be reached, and that Russian President Vladimir Putin would hold his end of any bargain.

"We're about to have a discussion about how we can make that work," said Starmer. "We've got to make sure it's a deal that lasts."

Trump, who came into office on January 20, has shocked traditional U.S. allies in Europe by drawing closer to Putin, calling Ukrainian President Volodymyr Zelenskyy a "dictator," and demanding payback for U.S. financial support for Kyiv.

Zelenskyy is expected to be in Washington on Friday to sign an agreement with Trump on rare earth minerals, a deal the Ukrainian leader said would hinge on further U.S. aid. Trump portrays the deal as a way to recoup American money that has been spent to support Ukraine. It includes no specific security guarantees for Ukraine, a U.S. official said.

Starmer has signaled that Britain will increase defense spending and is expected to try to reassure the U.S. president that Europe will provide support and security guarantees to Kyiv if peace talks with Russia are successful.

A senior Trump administration official told reporters they were pleased with Starmer's pledges to increase defense spending.

Putin on Thursday warned "Western elites" against trying to sabotage a potential rapprochement between Russia and the United States, saying Moscow would use its diplomats and intelligence services to thwart such efforts. The remarks were an apparent reference to the European Union and Britain.

Trump has shattered foreign policy and domestic policy norms since the start of his second term, rattling allies by advocating for U.S. ownership of the Gaza Strip and by promising trade tariffs on U.S. friends and foes alike.

"We would want any economic relationship with the UK to be based on reciprocal and equal trade," the Trump aide said.

In the Oval Office, Trump complained about trade relations with the European Union, which Britain left in 2020.

"On our trade, obviously, it is fair and balanced," Starmer interjected, "and in fact you've got a bit of surplus so we're in a different position." The U.S. has a trade surplus in goods with Britain, according to U.S. government statistics.

Meanwhile, U.S. Vice President JD Vance, who also attended the meeting, said the leaders would discuss what he described as "infringements on free speech" in Britain that have affected American technology companies.

"We've had free speech for a very, very long time in the United Kingdom," Starmer responded.

Trump's relationship with Starmer got off to a friendly start in September with a two-hour dinner in New York at Trump Tower. The British leader's team said the atmosphere was warm with a "gracious host."

Like Macron, Starmer will argue that a rushed peace deal with Russia, without the participation of Ukraine or European nations, might lead to further instability in Europe, which would not be good for the United States.

Starmer has said he is open to British troops providing security guarantees to Ukraine but only alongside other European nations and with "the right conditions in place."

European countries are concerned about the high level of conflict in Ukraine now, the U.S. official said, while a ceasefire would give them more comfort that their role is more about peacekeeping than deterring active conflict.

"The type of force depends very much on the political settlement that is made to end the war," the U.S. official said. "That trade-off is part of what the leaders today are going to be discussing."