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North Korean leader Kim Jong Un said he sees no reason to continue his self-imposed moratorium on nuclear and long-range missile tests, warning the world will soon see "a new strategic weapon" unveiled by his country in the near future.

However, in the comments published Wednesday, Kim also appeared to leave the door open to diplomacy, suggesting that tests would only resume if Washington did not change its policies.

North Korea has suspended nuclear and intercontinental ballistic missile tests since an unprecedented flurry of activity in 2017. But during that time, negotiations that Washington hoped would lead to Kim giving up his nuclear arsenal have fallen apart.

In the comments released Wednesday, Kim complained that his country's suspension of nuclear and ballistic missile tests had been repaid by the U.S. holding military drills with South Korea and imposing more sanctions on his isolated country.

He said that "under such conditions" there was "no ground" to continue suspending tests. "This is chilling our efforts for worldwide nuclear disarmament and non-proliferation," he said.

The remarks were made at a four-day meeting of his Workers' Party’s Central Committee and reported by North Korea's state-controlled news agency, KCNA.

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Late Tuesday, President Donald Trump urged Kim to stick to an agreement signed at a historic summit in Singapore in June 2018. It was the first time sitting leaders from these historical enemies had met in person, but their agreement for North Korea to "denuclearize" was widely criticized by experts as vague to the point of being almost meaningless.

"Look, he likes me, I like him, we get along," Trump said at a New Year's party at Mar-a-Lago. "But he did sign a contract, he did sign an agreement talking about denuclearization ... I think he’s a man of his word so we’re going to find out, but I think he’s a man of his word."

Previously, North Korea had threatened to deliver a "Christmas gift" to the U.S. — raising the possibility of another weapons test. On Tuesday, Trump said, "I know he's sending out certain messages about Christmas presents and I hope his Christmas present is a beautiful vase. That's what I'd like, a vase."

According to state-media's report of the four-day meeting, Kim "confirmed that the world will witness a new strategic weapon to be possessed by the DPRK in the near future," referring to North Korea's official name, the Democratic People's Republic of Korea. It did not provide details about what this weapon might be.

Kim also said his country would take "shocking actual action to make [the U.S.] pay for the pains sustained by our people."

Many analysts and officials think that Kim will never give up his nuclear arsenal, which is estimated to contain up to 40 warheads and is seen by the repressive, authoritarian country as key to the survival of the Kim dynasty that has ruled it for more than 70 years.

However, there were elements in Kim's remarks that suggest his regime is willing to discuss the extent and power of this arsenal in exchange for sanctions relief.

"The scope and depth of bolstering our deterrent will be properly coordinated depending on the U.S. future attitude to the DPRK," he said.

Vipin Narang, a politics professor at the Massachusetts Institute of Technology who focuses on nuclear weapons, tweeted the potential to negotiate on this issue is "the door we should urgently push on."

Others noted that although Kim said he saw no reason to continue suspending tests, he had not resumed them yet.

"We should be grateful that he’s all talk and no action at this point; the subtext: Kim is leaving room for diplomacy," tweeted Jean H. Lee, a Korea expert at the Wilson Center.