North Korean leader Kim Jong-un called for "positive and offensive measures" to ensure the country's security before a year-end deadline he has set for denuclearisation talks with the United States.

Mr Kim convened a weekend meeting of top Workers' Party officials to discuss policy matters amid rising tension over his deadline for the US to soften its stance in stalled negotiations aimed at dismantling North Korea's nuclear and missile programs.

At a session on Sunday, Mr Kim suggested action in the areas of foreign affairs, the munitions industry and armed forces, stressing the need to take "positive and offensive measures for fully ensuring the sovereignty and security of the country," North Korea state media KCNA said.

The meeting was the largest plenary session of the party's 7th Central Committee since its first gathering in 2013 under Mr Kim, according to South Korea’s Unification Ministry handling inter-Korean affairs.

The committee also met in 2018 and in April but on a much smaller scale.

KCNA said the meeting was still under way. It was the first time the gathering had lasted more than one day since Mr Kim took power in late 2011, ministry spokesman Lee Sang-min told a regular briefing.

The United States was watching the end-of-year meeting closely and hoped North Korea would choose peace over confrontation, Secretary of State Mike Pompeo said on Monday.

"We still maintain our view that we can find a path forward to convince the leadership in North Korea that their best course of action is to create a better opportunity for their people by getting rid of their nuclear weapons," Mr Pompeo told Fox News.

North Korea has urged the US to offer a new approach to resume negotiations, warning that it may take an unspecified "new path" if they fail to meet its expectations.

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US military commanders said the move could include the testing of a long-range missile, which North Korea has suspended since 2017, along with nuclear warhead tests.

The US would be "extraordinarily disappointed" if North Korea tests a long-range or nuclear missile, White House national security adviser Robert O'Brien said on Sunday.

He also vowed to take appropriate action as a leading military and economic power.

The United States had opened channels of communication with North Korea and hoped Kim Jong-un would follow through on denuclearization commitments he made at summits with US President Donald Trump, Mr O'Brien said.

A video released by the US Air Force and reviewed by Reuters showed a simulation of an Aegis destroyer spotting what appeared to be a North Korean inter-continental ballistic missile being fired towards the Pacific over the skies of Japan, prompting the launch of ground interceptor missiles.

The 65-second clip was dated September and released on 2 December on the website of the US Defense Visual Information Distribution Service.

A South Korean military source said while it was largely a regular promotional video, its release coincided with heightened tensions amid a recent series of North Korean weapons tests and a war of words between North Korea and the US.