Prime Minister Shinzo Abe declined on Monday to comment on a claim by U.S. President Donald Trump that he’d nominated the American leader for this year’s Nobel Peace Prize, but did not deny the assertion, instead praising Trump’s efforts to defuse the North Korean nuclear crisis.

“I’m not saying it’s untrue,” Abe told a Budget Committee session of the Lower House.

“The Nobel committee doesn’t reveal who submits nominations, or those who were nominated, for fifty years. In accordance with this policy, I’d like to refrain from commenting,” he added.

In response, opposition lawmakers argued that suggesting peace had already been achieved in the region would be inaccurate, and at odds with the nation’s recent decision to purchase new missile defense systems.

Abe’s remarks followed Trump’s surprising claim Friday that Japan’s prime minister had nominated him for the Nobel Peace Prize, for his work toward easing tensions with North Korea last year.

On Sunday, the daily Asahi Shimbun reported that Abe had nominated Trump for the prize after the U.S. government sounded the Japanese leader out over a possible nomination, citing an unnamed government source.

According to Nobel rules, “neither the names of nominators nor of nominees for the Nobel Peace Prize may be divulged until 50 years have elapsed.”

This year there are 304 candidates for the Nobel Peace Prize, out of which 219 are individuals and 85 are organizations, the Nobel Committee has said. The submission deadline was Jan. 31.

Abe’s reported nomination of Trump, if true, may have been based on his pragmatic view of the Nobel Peace Prize. In October 2014, Abe reportedly told ex-Defense Minister Shigeru Ishiba that nominations for the peace prize are “rather politically motivated.”

Abe has tried to build a close relationship with Trump, partly because of his aspiration to keep the U.S. committed to the defense of Japan and its allies from the North Korean nuclear and missile threat.

The Japanese leader’s efforts have included many summit meetings and teleconferences with the U.S. president, pledges to buy expensive weapon systems produced by U.S. firms and even a red-carpet reception for Ivanka Trump when she visited Japan in November 2017.

“President Trump has been decisively working to resolve the nuclear and missile issues of North Korea. He held a historic meeting” with North Korean leader Kim Jong Un in June, Abe told Monday’s Budget Committee session.

Trump is also fully cooperating with Tokyo in trying to resolve the issue of Japanese nationals abducted by North Korean agents, Abe said.

“Cooperating hand-in-hand with President Trump, I’d like to make all-out efforts to resolve the nuclear and missile issues as well as the abduction issue, as the most important agenda for our country,” Abe said.

Abe was answering questions from Yuichiro Tamaki, who heads the Democratic Party for the People, the second largest opposition force. Tamaki immediately criticized Abe’s response.

“You can’t comment on (the report), which I believe means you actually nominated” Trump for the prize, Tamaki said.

“If you believe the current situation in Northeast Asia is peaceful, I think it’s a problem,” Tamaki said.

“Nothing has been resolved. None of the abduction, nuclear and missile issues were resolved,” including those involving short- to medium-range ballistic missiles that are capable of directly hitting Japan, Tamaki said.

“We cannot help but say you are looking at the situation too optimistically. On top that, it would send a terribly inaccurate message to the world,” Tamaki argued.

Tamaki also said that the nomination, if true, would conflict with Japan’s decision to introduce two Aegis Ashore anti-missile defense systems.

Japan has decided to introduce the weapons systems — estimated to cost about ¥600 billion in total — citing the “imminent threat” of North Korean ballistic missiles.

The comment from Trump came Friday in a speech from the Rose Garden of the White House, when he said that Abe had sent a “most beautiful five-page letter” to the Nobel committee to nominate him for the prize .

Trump said he thanked Abe at the time, but added that he did not expect to win the prize, and that that was “OK.”

The U.S. leader said his work on the North Korean issue had prompted the move, noting that Abe “had rocket ships and … missiles flying over Japan, and they had alarms going off. … Now all of a sudden they feel good, they feel safe. I did that.”