North Korea conducted a “very important test” at a long-range missile launch site that the reclusive regime had promised to close as part of nuclear weapons talks with the United States, state media reported on Sunday.

The development comes as Pyongyang has warned it would seek a “new path” with the stalled denuclearization talks if the US fails to make major concessions by the end of the year, according to KCNA, the Korean Central News Agency.

The test occurred Saturday at the Sohae Satellite Launching Ground and will have an “important effect on changing the strategic position of (North Korea) once again in the near future,” a spokesman for the North’s Academy of National Defense Science said in a statement carried by KCNA.

North Korean President Kim Jong-un agreed to dismantle the Sohae facility during talks with President Trump in Singapore last year, but reports in March said it was being restored.

North Korea didn’t elaborate on what the test included.

Missile experts said it appears North Korea tested a rocket engine rather than a missile launch, which are typically quickly detected by South Korea.

South Korea and the US closely monitor activity at such sites.

“If it is indeed a static engine test for a new solid or liquid fuel missile, it is yet another loud signal that the door for diplomacy is quickly slamming, if it isn’t already,” Vipin Narang, a nuclear affairs expert at the Massachusetts Institute of Technology, told Reuters.

“This could be a very credible signal of what might await the world after the New Year,” Narang said.

Solid fuel increases a weapon’s mobility and lessens the amount of preparation time for a launch. In the past, North Korean long-range missiles used liquid fuel.

Pyongyang informed the United Nations on Saturday that denuclearization talks with Washington are not needed.

“The results of the recent important test will have an important effect on changing the strategic position of the DPRK once again in the near future,” KCNA reported, referring to North Korea’s official name, the Democratic People’s Republic of Korea.

North Korea, which launched two short-range projectiles last month, has been ramping up its rhetoric against the Trump administration.

It once again referred to Trump as a “dotard” last week after the president called Kim “Rocket Man.”

A dotard refers to an elderly person with weakening mental or physical capabilities.

Asked on Saturday about reestablishing negotiations with North Korea, Trump said he and Kim have a good relationship.

“I think we both want to keep it that way. He knows I have an election coming up. I don’t think he wants to interfere with that. But we’ll have to see,” Trump said at the White House.

With Post wires