After sources said Trump might not meet with the foreign leader while he is in the U.S., Trump told reporters on Thursday they will meet at 9:45 ET this morning at Trump Tower.

"It's a shame what's happening in Ukraine. So many deaths, so much destruction," Trump said. "It's a horrible thing. And one of the things that are very bothersome to me is the fact that Europe is paying only a small fraction of the money that the United States of America is paying, and we have an ocean between Russia and ourselves."

ABC News Senior Congressional Correspondent Rachel Scott asked Trump if he believed Ukraine should cede its own territory to Russia in order to end the war -- what Kamala Harris called "surrender."

"We'll see what happens," Trump said. "Let's get some peace. We need peace. We need to stop the death and destruction, don't you think? Wouldn't that be nice?"

The Secret Service informed Trump’s campaign it wouldn’t be able to accommodate his outdoor rally in Wisconsin on Saturday due to manpower issues, according to a source briefed on the situation.

The campaign wanted to have a rally at an airport hangar, but due to the Secret Service being stretched thin with the U.N. General Assembly in New York, it didn’t have the number of agents necessary to secure that site. A source said Secret Service personnel and equipment are being pushed to their limits to sustain the current operational tempo.

Trump’s detail is akin to those of President Joe Biden and Harris, with the exception of Defense Department assets on their details, and the agency wasn’t built to handle these increasing needs, according to a source familiar with the planning.

"Former President Donald Trump is receiving heightened levels of U.S. Secret Service protection and our top priority is mitigating risks to ensure his continued safety at all times,” Anthony Gugliemi, Secret Service chief of communications, said. “Out of concern for operational security, we cannot provide specific details about resources allocated for event security or communications between agency personnel and our protectees."

The Trump campaign hasn’t responded to ABC News’ request for comment.

Trump blasted Harris' record as he spoke about immigration at Trump Tower in New York, .

"Kamala Harris will be visiting the southern border that she has completely destroyed, from what I understand, tomorrow," Trump said. "Why would she go to the border now, playing right into the hand of her opponent? I mean, you take a look at this -- why would you do that? There can be no justification for what she’s done."

Trump is going through a lengthy list of his grievances with Harris and continued to demonize migrants.

In a last-minute addition to his schedule, Trump's campaign announced that he will deliver remarks Thursday at Trump Tower at 4:30 p.m. ET.

The campaign didn't disclose the topic of his remarks, but they will happen on the same day that New York City Mayor Eric Adams has been charged with five counts connected to improper campaign contributions, according to a sweeping indictment unsealed Thursday morning.

This weekend, Trump will campaign in Michigan and Wisconsin.

-ABC News' Lalee Ibssa, Soorin Kim and Kelsey Walsh