North Korea has fired a suspected ballistic missile off its east coast, authorities in the region report, underscoring leader Kim Jong-un’s New Year vow to bolster his country’s military capability.

Japan’s coast guard, which first reported the launch, said it could be a ballistic missile but did not provide further details.

“Since last year, North Korea has repeatedly launched missiles, which is very regrettable,” Japanese Prime Minister Fumio Kishida told reporters.

South Korea’s Joint Chiefs of Staff said nuclear-armed North Korea fired a presumed ballistic missile from an inland location toward the sea.

“Our military is maintaining readiness posture in preparation for a possible additional launch while closely monitoring the situation in close co-operation with the United States,” the JCS said in a statement.

United Nations Security Council resolutions ban all ballistic missile tests by North Korea, and have imposed sanctions.

In state media summaries of a speech Mr Kim gave ahead of the new year, the North Korean leader did not specifically mention missiles or nuclear weapons, but said that national defence must be bolstered.

North Korea is under international sanctions over its nuclear weapons program but since the start of the COVID-19 pandemic it has become even more isolated, imposing border lockdowns that have slowed trade to a trickle, and choking off any in-person diplomatic engagements.

It has also stuck to a self-imposed moratorium on testing its largest intercontinental ballistic missiles or nuclear weapons.

The last tests were in 2017, before Mr Kim launched a diplomatic overture to the United States and South Korea that has since stalled.

But the country has continued test firing new, short-range ballistic missiles, including one launched from a submarine in October.

For the first time in his 10 years of rule, Mr Kim did not publicly appear at any missile tests or military drills last year, according to an analysis by NK News, a Seoul-based website that monitors North Korea.

Health issues or efforts to minimise attention may have played a role in his official absences, the site said.

Mr Kim’s latest speech made no mention of efforts by South Korea to restart stalled negotiations, or offers by the United States to talk without preconditions, casting doubts on South Korean President Moon Jae-in’s push to achieve a breakthrough before his term ends in May.

North Korea continues to advance its nuclear weapons and missile programs despite United Nations Security Council sanctions and high-level diplomatic efforts, the US government’s Congressional Research Service concluded in a report last month.

“Recent ballistic missile tests and military parades suggest that North Korea is continuing to build a nuclear warfighting capability designed to evade regional ballistic missile defences,” the report said.