SEOUL • North Korean leader Kim Jong Un visited the test site of a new tactical weapon in his first such public inspection since last year, hailing it as a "display of our rapidly growing defence capabilities", state media said yesterday.

The North's first mention of a new weapons development in months threatens to sour the political atmosphere as negotiations between Pyongyang and Washington appear to have stalled.

"This result today is a justification of the party's policy focused on defence science and technology, another display of our rapidly growing defence capabilities to the whole region, and a ground-breaking change in strengthening our military's combat capabilities," Mr Kim said.

The test was successful, and the weapon could protect North Korea like a "steel wall", its KCNA news agency reported, adding that Mr Kim had observed "the power of the tactical weapon".

The only picture released by state media showed Mr Kim standing on a beach surrounded by officials in military uniforms, but no weapons were visible.

International weapons experts said the officials around Mr Kim included a leader of the artillery corps of the Korean People's Army.

In Washington, in response to the North Korean announcement, a US State Department spokes-man said: "We remain confident that the promises made by President Trump and Chairman Kim will be fulfilled."

The official was referring to an unprecedented summit between United States President Donald Trump and Mr Kim in Singapore in June, where they agreed to work towards denuclearisation and peace on the Korean peninsula, and establish new relations with each other.

But the agreement was short on specifics, and negotiations have made little headway since.

South Korea's Defence Ministry said it did not have an immediate comment but was preparing a statement on the North Korean test.

Mr Kim said the weapons system tested was one in which his father Kim Jong Il had taken a special interest during his lifetime, personally leading its development.

Mr Kim's last publicised military inspection was the launch of the Hwasong-15 intercontinental ballistic missile (ICBM) on Nov 29 last year, though he engaged in at least eight other military-related activities this year, the South's Unification Ministry said.

The North Korean leader this year declared his nuclear force complete, and said he would focus on economic development.

North Korea has continued to showcase its conventional military capabilities, including at a large military parade in Pyongyang, its capital, on Sept 9.

But any testing of new weapons threatens to raise tensions with Washington, which has said there will be no easing of international sanctions until North Korea takes more concrete steps to abandon its nuclear weapons or long-range missiles.

Pyongyang has increasingly expressed frustration at Washington's refusal to ease sanctions, and recently threatened to restart development of its nuclear weapons if more concessions were not made.

"They are trying to signal that they are willing to walk away from talks and restart weapons testing," said Dr Adam Mount of the Federation of American Scientists.

A meeting in New York planned this month between US Secretary of State Mike Pompeo and North Korean Kim Yong Chol, a senior aide to Mr Kim, was postponed.

On Thursday, US Vice-President Mike Pence said that Mr Trump planned to meet Mr Kim Jong Un again next year and will push for a concrete plan outlining Pyongyang's moves to end its arms programmes.

REUTERS