WASHINGTON -- US President Donald Trump said Wednesday he is doing everything possible to have a "very successful" meeting with North Korean leader Kim Jong-un, but added he will walk away from the summit if it is unlikely to bear fruit.

"I hope to have a very successful meeting," he said in a joint press conference with Japanese Prime Minister Shinzo Abe in Florida. "If I think it's a meeting that is not going to be fruitful, we are not going to go. If the meeting, when I'm there is not fruitful, I will respectfully leave the meeting."

Trump plans to meet Kim in May or early June to discuss the denuclearization of the peninsula. The summit, if held, will be unprecedented for the two countries that have no diplomatic relations with each other.

The Washington Post reported Tuesday that Trump sent his nominee for secretary of state, Mike Pompeo, to the North to meet Kim over Easter weekend. Trump confirmed later that Pompeo, current director of the Central Intelligence Agency, went to Pyongyang and formed a "good relationship" with the North's leader.

"We will not repeat the mistakes of previous administrations," Trump told reporters following two days of talks with Abe. "Our campaign of maximum pressure will continue until North Korea denuclearizes."

Past negotiations and agreements with Pyongyang led to a temporary freeze of its nuclear facilities in exchange for economic aid. The deals collapsed when North Korea was found to be running clandestine nuclear programs.

The Trump administration has led a campaign of increased economic sanctions and diplomatic isolation to force Pyongyang back to denuclearization talks following its sixth nuclear test and three intercontinental ballistic missile launches last year.

"We hope to see the day when the whole Korean Peninsula can live together in safety, prosperity and peace," Trump said. "This is the destiny of the Korean people, who deserve and have gone through so much over the years. We hope it all works out, and we'll be trying very hard."

Trump offered a "bright path" in the event the North denuclearizes in a complete, verifiable and irreversible manner.

The US is negotiating for the release of three Americans held in the North and will also do everything it can to secure the return of Japanese citizens who were abducted by the regime decades ago, he added.

He again took credit for the success of the Winter Olympics in PyeongChang, South Korea, in February. In what was dubbed a "charm offensive," Kim sent a delegation of athletes and officials to the games as tensions spiked over possible US military action against Pyongyang.

"President Moon (Jae-in) of South Korea was very generous in what he said: If it weren't for Donald Trump, the Olympics would've been a total failure. It was my involvement and the involvement of our great country that made the Olympics a very successful Olympics," Trump said. "So we've gotten us here, and I think we're going to be successful. But if for any reason I feel we're not, we end."

Abe said the North Koreans should get no reward for simply having dialogue.

"Maximum pressure should be maintained and actual implementation of concrete actions toward denuclearization will be demanded," he said.

The Koreas are planning to hold their own summit on the inter-Korean border next week. The agenda will include a possible peace treaty to formally end the 1950-53 Korean War. (Yonhap)