President Donald Trump reacted to the announcement of a ballistic missile engine missile test by North Korea, saying it endangers his "special relationship" with North Korean dictator Kim Jong-un. Trump also made mention of North Korea not interfering in the U.S. presidential election in November 2020.

Trump asserts Kim will “lose everything” if he again re-opens hostilities against the United States, especially since the new engine test was an outright violation of an agreement both reached in Singapore on June 12, 2018. He again repeated the "North Korean Economy Can Be Great" argument that promises the country economic prosperity if it denuclearizes on U.S. terms.

“Kim Jong Un is too smart and has far too much to lose, everything actually, if he acts in a hostile way. He signed a strong Denuclearization Agreement with me in Singapore,” tweeted Trump on Sunday. “He does not want to void his special relationship with the President of the United States or interfere with the U.S. Presidential Election in November."

Trump also reminded Kim of the latter's commitment and said his regime "must denuclearize as promised. NATO, China, Russia, Japan, and the entire world is unified on this issue!"

After the Singapore summit, Trump boasted Kim had agreed to the "complete denuclearization" of the Korean Peninsula -- but without explaining what each side understood by denuclearization. Trump boasted North Korea was "already destroying a major missile engine testing site."

That major missile engine testing site was Sohae Satellite Launching Station, which again became operational earlier this month. Kim sent a decidedly unloving missive to Trump Sunday by announcing North Korea had carried out a sucessful and “very important” test at Sohae, which is located in northwestern North Korea along the shores of the Yellow Sea.

KCNA, the state-owned news agency, called the test a “successful test of great significance” without specifying what was tested at Sohae at the time. Western missile experts later revealed North Korea had conducted a static test of a rocket engine (possibly an intercontinental ballistic missile engine) rather than a missile launch.

Kim Jong-un This picture, taken and released Jan. 1, 2018, by North Korea's official Korean Central News Agency (KCNA), shows North Korean leader Kim Jong Un delivering a New Year's speech at an undisclosed location. Photo: Getty Images

“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,” contends Vipin Narang, a nuclear affairs expert at the Massachusetts Institute of Technology (MIT), CNBC noted. “This could be a very credible signal of what might await the world after the New Year.”

What also alarms experts isn't that the static test took place. It's that the test was conducted at Sohae, which is supposed to be non-operational after international observers in October 2018 confirmed the site was being dismantled in accordance with a deal reached during the 2018 Singapore summit.

Experts believe North Korea began restoring Sohae after the 2019 North Korea-United States summit in Hanoi from Feb. 27 to 28 ended in abject failure after Trump hastily walked-out of the meeting after Kim refused to agree to all the U.S. demands.

It was later revealed Trump handed Kim a piece of paper demanding the transfer of North Korea’s nuclear weapons and missile material to the United States. Analysts said this was the first time Trump had precisely defined what he understood by denuclearization. This was also the first time Kim came to know of Trump's concept, which was based on the "Libya model" Kim is known to despise. Trump walked out of the summit after Kim rejected this proposal.