GEOFF BENNETT: Welcome to the "News Hour."

President Trump today continued his pressure campaign on Ukraine, insinuating that President Volodymyr Zelenskyy should step down if he doesn't want a peace deal.

That follows their unprecedented clash in that Friday Oval Office meeting.

Western leaders have been scrambling to help mend the relationship, but also make plans to maintain support for Ukraine if the U.S. walks away.

Nick Schifrin reports.

NICK SCHIFRIN: In the White House today, President Trump kept up pressure on Ukraine's embattled president.

DONALD TRUMP, President of the United States: I just think you should be more appreciative, because this country has stuck with them through thick and thin.

NICK SCHIFRIN: He was even harsher on TRUTH Social, writing: "America will not put up with it for much longer," a response to this statement by President Volodymyr Zelenskyy yesterday.

VOLODYMYR ZELENSKYY, Ukrainian President (through translator): An agreement to end the war is still very, very far away, and no one has started all these steps yet.

DONALD TRUMP: Maybe somebody doesn't want to make a deal, and if somebody doesn't want to make a deal, I think that person won't be around very long.

That person will not be listened to very long.

You're gambling with the lives of millions of people.

VOLODYMYR ZELENSKYY: You think... DONALD TRUMP: You're gambling with World War III.

NICK SCHIFRIN: Today's rhetorical criticism highlights the substantive divide during Friday's Oval Office meltdown.

Ukraine doubts the very diplomacy with Putin the U.S. is prioritizing.

VOLODYMYR ZELENSKYY: What kind of diplomacy, J.D., you are speaking about?

what do you have -- what do you -- what do you mean?

J.D.

VANCE, Vice President of the United States: I'm talking about the kind of diplomacy that's going to end the destruction of your country.

NICK SCHIFRIN: Tonight, Zelenskyy stuck to his guns that diplomacy requires security guarantees.

VOLODYMYR ZELENSKYY (through translator): The baseline scenario is to hold positions and create conditions for proper diplomacy.

We need peace, real, fair peace, not endless war.

And we need security guarantees.

NICK SCHIFRIN: And the war stops for no politics.

This weekend, a Russian drone struck a residential apartment building in Kharkiv, one of countless Russian attacks on Ukrainian civilian targets.

KEIR STARMER, British Prime Minister: We are at a crossroads in history today.

NICK SCHIFRIN: In London this weekend, Prime Minister Keir Starmer led Zelenskyy and European leaders in an emergency summit that, in Starmer's words, assembled a coalition of the willing.

Europe is developing plans to deploy French, British and perhaps Eastern European troops into Ukraine to help enforce a cease-fire that French Foreign Minister Jean-Noel Barrot today said could be for one month and not include ground combat.

JEAN-NOEL BARROT, French Europe and Foreign Affairs Minister (through translator): This cease-fire in the air and at sea and on energy infrastructure will enable us to attest to the good faith of Vladimir Putin when he commits to the cease-fire.

NICK SCHIFRIN: But that's just one possibility, and European forces could not deploy without U.S. logistical and intelligence support.

KEIR STARMER: The discussions we have had today, particularly the coalition of the willing, is on the basis that this is a plan that we will work with, with the U.S. and that it will have U.S. backings.

NICK SCHIFRIN: It's also not clear Ukraine would support a cease-fire before agreed security guarantees.

COL. BOB HAMILTON (RET.

), Foreign Policy Research Institute: Zelenskyy's point was that, unless there are enforceable security guarantees backed by a credible deterrent force on the ground in Ukraine, Putin and Russia cannot be trusted.

NICK SCHIFRIN: Bob Hamilton is the head of Eurasia Research at the Foreign Policy Research Institute, who's visiting Ukraine this week.

COL. BOB HAMILTON: When the survival of your nation is at stake, it's not unreasonable for President Zelenskyy to insist on at least some assurances of security guarantees before he signs up to a cease-fire agreement, particularly one that he's not involved in negotiating.

NICK SCHIFRIN: Ukraine and Europe must also confront the possibility of losing U.S. military assistance.

Ukraine would struggle to replace American air defense and Western artillery.

But with more funding, it could rely more on domestically produced drones that are already causing the majority of Russian casualties.

COL. BOB HAMILTON: If those funds were provided by foreign countries, Ukraine could upscale its defense industrial production fairly quickly to double or triple it if it had the money.

NICK SCHIFRIN: For all the pressure that President Trump and his allies are maintaining on Zelenskyy, today, the president said the economic deal that Zelenskyy was supposed to sign on Friday before the meeting in the Oval Office went off the rails is still alive, depending, Geoff, on what Zelenskyy says and does.

GEOFF BENNETT: Meantime, Nick, what are you learning about what Zelenskyy is discussing with his fellow leaders in Europe?

NICK SCHIFRIN: Zelenskyy spoke to Baltic leaders this afternoon.

And a senior European official who was on that call told me that Zelenskyy sounded contrite about what had happened on Friday, and that he understood he needed to mend the relationship with Donald Trump.

From the Western, European perspective, we heard why in our story right there from Prime Minister Starmer, that European troops could not deploy into Ukraine without U.S. support, intelligence, and logistics.

The U.S. officials who are in favor of maintaining support for Ukraine had hoped that that economic deal would be signed on Friday as a way to convince the skeptical President Trump not only to continue support for Ukraine, but even invest in Ukraine's drone industry, which, as we said, is super important.

So whether he's willing to do that, whether, frankly, President Trump is willing to keep the same number of U.S. troops in Europe, well, all of that tonight, Geoff, lies in the balance.

GEOFF BENNETT: Nick Schifrin, thank you.

NICK SCHIFRIN: Thank you.