WASHINGTON — President Trump on Friday hailed the historic summit meeting between the leaders of North Korea and South Korea, and declared that in his own planned talks with the North he would not be fooled the way he said his predecessors had been on dismantling its nuclear weapons program.

“I don’t think he’s playing,” Mr. Trump said of the North Korean leader, Kim Jong-un, speaking with reporters in the Oval Office before a meeting with Chancellor Angela Merkel of Germany.

“The United States has been played beautifully, like a fiddle, because you had a different kind of a leader,” Mr. Trump went on. “We’re not going to be played, O.K.? We’re going to hopefully make a deal; if we don’t, that’s fine.”

Mr. Trump spoke after a groundbreaking meeting between Mr. Kim and President Moon Jae-in of South Korea in the Demilitarized Zone between the North and South. The two leaders agreed to work to remove all nuclear weapons from the Korean Peninsula and, within a year, pursue talks with the United States to declare an official end to the Korean War, which raged from 1950 to 1953.