North Korea says it has carried out another "crucial test" at its long-range rocket launch site.

The announcement comes as North Korea continues to pressure Donald Trump over a deadline set for the end of the year by leader Kim Jong Un to salvage faltering nuclear negotiations.

North Korea's Academy of Defence Science did not specify what was tested on Friday.

Image: Kim Jong Un attending the test of a multiple rocket launcher in August

Days earlier, the North said it conducted a "very important test" at the site, prompting speculation that it involved a new engine for either a space launch vehicle or an intercontinental ballistic missile (ICBM).

Negotiations broke down after the US rejected demands by North Korea for relief on sanctions in exchange for a partial surrender of the North's nuclear capabilities at Kim's second summit with Mr Trump in Vietnam in February.


Talks resumed between the two leaders in June when they agreed to resume talks but a further meeting in October ended in deadlock over what North Korea called America's "old stance and attitude".

US Ambassador Kelly Craft was critical of the North's ballistic testing activity during a United Nations Security Council meeting - saying the tests were "deeply counterproductive" and risked jeopardising prospects for future talks.

North Korea has conducted 13 rounds of ballistic missile and rocket artillery tests since May and has hinted at lifting its moratorium on nuclear and long-range missile tests if the Trump administration fails to make substantial concessions.

Ms Craft also cited North Korean hints of "a resumption of serious provocations", which she said would mean they could launch space vehicles using long-range ballistic missile technology or test ICBMs "designed to attack the continental United States with nuclear weapons".

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The ambassador said that the US is "prepared to be flexible" and move towards an agreement on resuming talks.

But North Korea said her comments were a "hostile provocation" and warned that Washington may have squandered its chance of salvaging the fragile nuclear diplomacy.

Relations between the two countries have become ever more strained in recent weeks, with North Korea threatening to renew its insults at Mr Trump.

June: Trump and Kim's historic photo op

The North said it would consider him a "dotard" if he keeps using provocative language against Kim Jong Un.

The country's foreign ministry issued the warning days after the US president spoke of possible military action and revived his "rocket man" nickname for the North Korean ruler.

Choe Son Hui, Pyongyang's first vice foreign minister, said Mr Trump's remarks "prompted the waves of hatred of our people against the US" because they showed "no courtesy when referring to the supreme leadership of dignity" of North Korea.

August: N Korea launches 'very standard' - Trump

During a visit to London earlier this month, Mr Trump said his relationship with Mr Kim was "really good" but called for him to follow up on a commitment to denuclearise.

The president said: "We have the most powerful military we ever had, and we are by far the most powerful country in the world and hopefully we don't have to use it. But if we do, we will use it."

Mr Trump added that Mr Kim "likes sending rockets up, doesn't he? That's why I call him rocket man".

The president's comments prompted North Korea's military chief to warn that the use of force against the country would cause a "horrible" consequence for the US.