TOKYO — North Korea has sacked its foreign minister and replaced him with a former military officer with a reputation for being a hard-line, cantankerous negotiator, underlining a harsher attitude toward the United States.

Ri Yong Ho, who had served as foreign minister since 2016 and took charge of relations with the United States after the failed Hanoi summit with President Trump last year, has been replaced with Ri Son Gwon, diplomats said.

While experts cautioned against reading too much into leadership changes in the North Korean regime, the move appeared to underline leader Kim Jong Un’s decision to turn his back on negotiations with the United States, announced in a key speech on New Year’s Eve.

Ri Son Gwon is a former army colonel who does not come from the traditional elite diplomatic background of his predecessor. He has no previous experience in dealing with the United States but had served as Pyongyang’s point man on inter-Korean affairs since 2016, developing a reputation as a particularly testy negotiator.

He stormed out of the room during military talks with South Korea in 2014 when Seoul demanded an apology for what it saw as the North’s past military provocations, a former South Korean official told the Reuters news agency.

He was also accused of insulting South Korean conglomerate chiefs on a 2018 visit to North Korea on grounds they were not doing enough to boost business ties, according to South Korean lawmakers.

“Ri Son Gwon is generally known as a hard-liner — mainly due to his military background and his past comments to South Korean business executives and ministers — and it suggests that Ri may adopt a harder-line policy on the U.S.,” said Rachel ­Minyoung Lee, a senior analyst at NK News, which broke the news of the personnel shift on Saturday.

Lee said Ri Son Gwon has no experience on the nuclear issue, while his status in the regime hierarchy is nowhere close to that of his two immediate predecessors when they were appointed foreign minister.

In that sense, his appointment might signal a downgrading of U.S. relations within North Korea’s overall foreign policy, or a reduction of the Foreign Ministry’s role in relations with Washington, experts said, while cautioning that it was too soon to tell.

As a colonel in the Korean People’s Army, he played a leading role in military talks with the South, before going on to head in 2016 the Committee for the Peaceful Reunification of the Country, which handles relations with South Korea.

Duyeon Kim, a senior adviser with the International Crisis Group, said Ri’s appointment does not signal a policy shift, because the hard-line approach was already set by Kim in his New Year’s Eve speech. Instead, “the appointment means Kim is putting in place the people he thinks will implement his marching orders,” she said.

Experts said his predecessor, Ri Yong Ho, could have been demoted as a scapegoat for the breakdown of talks with the United States and Kim’s frustration with that process — but in the absence of word from Pyongyang, it was hard to be certain.

Nor is it clear whether Ri Son Gwon will play a leading role in relations with the United States. Experts say it is possible that experienced Vice Foreign Minister Choe Son Hui will continue to exercise hands-on responsibilities.

“Ri Son Gwon was infamous for his rough, unpolished, bully-like style during inter-Korean negotiations over the years,” said Duyeon Kim. “So, if he’s given any real negotiating role with Washington, then American negotiators will be in for a ride. But we will have to see whether Ri’s appointment is just symbolic.”

Kim reported from Seoul.