U.S. President Donald Trump voiced confidence Saturday that his agreement to meet North Korean leader Kim Jong Un was the right decision, saying that Japan is “very happy with what I’m doing” and that the talks could result in “the greatest deal for the world” that eases nuclear tensions.

“I may leave fast” if progress does not seem possible, Trump said at a televised campaign rally for Republican congressional candidate Rick Saccone in Pennsylvania. Trump said he believes North Korea wants to make peace and that, “I think it’s time.”

The mercurial U.S. president shocked both those inside and outside his administration on Thursday when he told visiting South Korean officials who had met Kim in Pyongyang for talks days earlier that he would be willing to accept the North Korean leader’s invitation to meet.

Trump also heaped praise on himself, saying that he had been the one who secured from Kim a commitment to denuclearizing the Korean Peninsula and a vow of a missile-test moratorium as long as talks were continuing.

The North conducted tests of its nuclear and missile programs at a torrid pace last year, including the launch of two intermediate-range missiles that flew over Hokkaido. In March, in an unusually overt threat to Japan, North Korea fired a simultaneous barrage of missiles that it said was training for a nuclear strike on U.S. military bases in the country — a type of saturation attack that experts said could leave the nation vulnerable.

“I wouldn’t say Japan was thrilled, missiles flying over” the country, Trump said at the rally, adding that now “they’re very happy with what I’m doing.”

But according to a Cabinet Office survey released Saturday, 85.5 percent of Japanese polled think the country is at risk of becoming involved in a war, a figure up 10 percentage points from the same poll in 2015.

Among the defense issues that most interested respondents was the situation on the Korean Peninsula, which topped the list at 68.6 percent.

The survey was conducted before news of the proposed Trump-Kim meeting.

At Saturday’s rally, Trump told the crowd that “a lot of people thought we were going to war” with North Korea. Now, he said, they were “thinking about denuclearization” and the planned meeting which would be the first ever between a sitting U.S. president and North Korean leader.

“Who knows what’s going to happen?” said Trump, who added that if the meeting takes place, he “may leave fast or we may sit down and make the greatest deal for the world and for all of these countries, including, frankly, North Korea.”

A time and place to meet has not yet been decided, although the summit is supposed to happen by the end of May.

Trump also boasted that his reducing the North Korean nuclear threat had helped save the Winter Olympics, which were held last month in South Korea.

“It’s a little hard to sell tickets when you think you are going to be nuked,” the president said.

Earlier in Washington, Trump sought to rally international support for the potential summit, noting the North’s missile pledge.

“North Korea has not conducted a Missile Test since November 28, 2017 and has promised not to do so through our meetings. I believe they will honor that commitment!” Trump wrote on Twitter.

Trump’s tweet, however, made no mention of nuclear tests and it was not clear which meetings he was referring to, as it was the high-level South Korean delegation last week that met with Kim, winning the missile and denuclearization pledges, as well as an “understanding” from Kim over annual joint U.S.-South Korean military exercises. The U.S. has not made public any direct discussions this year with the North on nuclear or missile issues and Pyongyang has not publicly confirmed any of its pledges conveyed to the South Korean delegation.

Trump also used Twitter on Saturday to characterize Prime Minister Shinzo Abe and Chinese President Xi Jinping as being supportive of the planned dialogue, yet did little to clear up confusion over the timing and any preconditions for the talks.

“Spoke to Prime Minister Abe of Japan, who is very enthusiastic about talks with North Korea,” Trump tweeted. That tweet also mentioned that the two had discussed “opening up Japan to much better trade with the U.S.” and “a massive $100 Billion Trade Deficit” with Tokyo that Trump called “not fair or sustainable.”

It was unclear if Trump had purposely linked North Korea to trade — and implicitly Abe’s support for whatever policy the White House takes toward Pyongyang — but the Japanese leader has been one of the most outspoken supporters of Trump’s “maximum pressure” campaign against the North, repeatedly deriding as worthless “talks for talks.”

Thursday’s surprise announcement of the possible Kim-Trump meet reportedly left Tokyo blindsided, stoking fears in the Abe administration that Japan might be marginalized, and its own goals relegated to the back burner.

In a separate tweet, Trump also wrote that Xi “told me he appreciates that the U.S. is working to solve the problem diplomatically rather than going with the ominous alternative.”

The White House has repeatedly said that “all options remain on the table,” including military action, to rein in North Korea’s nuclear drive — a prospect that has stoked concern in Tokyo, Seoul and even Washington.

But the recent thaw in intra-Korean ties has lessened concerns of a war that one U.S. lawmaker warned would be “very brief” and “of biblical proportions.”