Prime Minister Shinzo Abe declined to say whether he nominated Donald Trump for a Nobel Peace Prize, while praising the US president for “decisive" efforts to resolve the problems of a nuclear-armed North Korea.

Abe, who has worked hard to build a personal rapport with Trump, walked a fine line during a parliamentary committee meeting Monday when asked about Trump’s claim from Friday that the Japanese leader had put his name forward for the prize.

“I am not saying it’s not true," he told an opposition lawmaker, adding that the Nobel committee doesn’t reveal nominations and he would refrain from commenting.

Abe praised Trump for his diplomacy with North Korea and helping to protect Japan, which relies on the US military for its defence. “President Trump has acted decisively toward resolving the issues of the North Korean nuclear and missile problems," Abe said.

Abe was one of the first world leaders to embrace Trump after the 2016 presidential election. Even though surveys in Japan show high public disapproval of Trump, there has been no major backlash to Trump’s plans to visit Japan again this year, while such visits have touched off protests in places such as the UK.

Abe’s efforts to build one-on-one ties with Trump have shown their limits. Japan was forced to accept bilateral trade talks with the US after Trump threatened tariffs on its vital auto industry. The US Commerce Department has delivered a report to Trump on the security implications of auto imports, without making its findings public.

In a speech on border security in the White House’s Rose Garden on Friday, Trump said Abe had shown him a copy of a five-page letter he sent to “the people who give out a thing called the Nobel Prize". The president was responding to a question on progress made since last year’s historic summit with North Korea. The Asahi newspaper of Japan said the nomination had been made after a request from the US.

Japanese opposition lawmaker Junya Ogawa told parliament on Monday that it was “shameful for Japan" to be nominating Trump for the prize. The US president had disrupted the world order by withdrawing from the Paris climate accord, breaking a multilateral nuclear deal with Iran and other acts, he said.

South Korean President Moon Jae-in, who is pushing to improve ties with North Korea, weighed in Monday, saying through a spokesman that Trump deserved the Nobel Peace Prize.

“The president has repeatedly emphasized that President Trump’s leadership and decisiveness have played a crucial role in establishing peace on the Korean peninsula, so it is President Moon’s belief that he well deserves the Nobel Peace Prize," Kim Eui-keum, said at a briefing Monday.

The two Koreas remain technically at war and between them station about 1 million soldiers near their border.

Trump is planning to have a second summit with North Korean leader Kim Jong Un in Hanoi 27-28 February after an unprecedented meeting last year. Their June discussions in Singapore led to a joint statement on North Korea’s denuclearization but the words have not led to concrete steps to roll back Pyongyang’s atomic ambitions.

The Hanoi meeting brings both the promise of a less-dangerous North Korea and the potential peril of a weak deal that leaves Japan exposed to Kim’s weapons of mass destruction.

Abe said Trump raised Japan’s concerns about its citizens abducted decades ago by North Korea when he met Kim. Abe also told parliament he will do everything possible to work with Trump to resolve the North Korean nuclear and missile problems as well as the abduction issue.

Bloomberg's Youkyung Lee contributed to this story.