This article is more than 9 months old

This article is more than 9 months old

Donald Trump said on Sunday North Korean leader Kim Jong-un risks losing “everything” and his country must denuclearize, after the North said it had carried out a “successful test of great significance”.

“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,” Trump said on Twitter, referring to his first summit with Kim in 2018.

The Guardian view on North Korea: a brewing nuclear crisis | Editorial Read more

“He does not want to void his special relationship with the President of the United States or interfere with the US Presidential Election in November.”

North Korea’s state media KCNA reported earlier that it had carried out a “very important” test at its Sohae satellite launch site, a rocket-testing ground US officials once said North Korea had promised to close.

Pyongyang’s last nuclear test, its sixth and most powerful, took place in September 2017.

On CBS’s Face the Nation on Sunday, the US national security adviser, Robert O’Brien, said resuming tests “would be a mistake on the part of North Korea”.

If North Korea takes a different path than the one it’s promised … we’ve got plenty of tools in the toolkit Robert O'Brien

“It doesn’t end well for them if they do,” O’Brien said. “If North Korea takes a different path than the one it’s promised … we’ve got plenty of tools in the toolkit.”

The reported test came ahead of a year-end deadline North Korea has imposed for the US to drop its insistence on unilateral denuclearization. Pyongyang has warned it could take a “new path” amid stalled talks.

“North Korea, under the leadership of Kim Jong-un, has tremendous economic potential, but it must denuclearize as promised,” Trump wrote.

The KCNA report heralded a “successful test of great significance” but did not specify what was tested. Missile experts said it appeared likely the North Koreans had conducted a static test of a rocket engine, rather than a missile launch.

“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,” said Vipin Narang, a nuclear affairs expert at the Massachusetts Institute of Technology. “This could be a very credible signal of what might await the world after the new year.”

North Korea has called on the US to change its policy of unilateral denuclearization and demanded relief from punishing sanctions. On Saturday North Korea’s ambassador to the UN said denuclearization was off the table and lengthy talks with Washington were 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 said, using the initials of North Korea’s official name, the Democratic People’s Republic of Korea.