President Trump said Tuesday that his next summit with North Korean leader Kim Jong Un will not happen until after next month’s midterm elections.

“I just can’t leave now,” Trump told reporters aboard Air Force One, saying his hectic campaign-trail schedule has left him too busy to arrange a meeting.

Trump last week held four rallies for Republican candidates across the country. He headlines another four this week, including an event Tuesday evening in Iowa.

Earlier Tuesday, in an Oval Office meeting with outgoing U.N. ambassador Nikki Haley, Trump said that his staff is looking at “three or four locations” for the summit. He also predicted that North Korea “is going to be a very successful country.”

“I think it’s going to be incredibly economically successful, and I want to make it that way,” Trump said. “I think it’s going to be good.”

Relations between Washington and Pyongyang have run hot and cold in recent months. A July trip by Secretary of State Mike Pompeo to North Korea ended with officials there accusing the United States of making “gangster-like” demands over denuclearization. An August visit by Pompeo was abruptly called off.

But things seemed to go better this week.

On Sunday, Pompeo spent more than three hours with Kim in Pyongyang, in talks he described as a “productive” step toward persuading North Korea to abandon its nuclear weapons program. Pompeo also announced that both sides had agreed to set up “working level” teams to finalize the date and time for a second summit to follow June’s Trump-Kim meeting in Singapore.

Asked Tuesday about the potential location for a second summit, Trump said he was open to meeting in North Korea or in the United States — including at Trump’s Mar-a-Lago Club in Palm Beach, Fla.

“I think eventually we’re going to have lots of meetings on U.S. soil and on their soil, by the way, just — you know, that’s a two-way street,” he said.

Trump has another big summit on his agenda after the midterms: The White House announced in July that it was pushing to 2019 a second meeting between Trump and Russian President Vladi­mir Putin.

Simon Denyer in Tokyo contributed to this report.