The North did not say what was tested on Saturday. But South Korea's Joint Chiefs of Staff said that nothing has been fired from the North's Sohae satellite launching station, also known as Donchang-ri site, reports Yonhap News Agency.
"A very important test took place at the Sohae Satellite Launching Ground on the afternoon of December 7, 2019," Pyongyang said in a statement carried by the state-run Korean Central News Agency (KCNA), adding the Academy of National Defense Science reported the "result of the successful test" to the Workers' Party.
"The results of the recent important test will have an important effect on changing the strategic position of North korea once again in the near future," it added.
The North has reportedly shown signs of preparing for a missile engine test at the site recently, and Sunday's claim could mean that it has successfully tested a new rocket engine that could be used in the launch of a new long-range rocket or an intercontinental ballistic missile (ICBM).
The test came as Pyongyang has ramped up pressure on the US to meet its demand for a new negotiating proposal by year's end, strongly suggesting that otherwise, it could restart testing of nuclear weapons and ICBM.
The North last conducted a nuclear test in September 2017 and an ICBM test in December 2017, though it recently carried out a series of short-term ballistic missile and projectile firings, said Yonhap News Agency.
Nuclear talks have been stalled since the summit between Kim and US President Donald Trump in February broke down as they remained far apart over how to match Pyongyang's denuclearization steps with Washington's sanctions relief and other concessions.
In April, leader Kim demanded Washington come up with acceptable proposals in their denuclearization negotiations before the end of this year. He said that he could take a "new way" if Washington fails to do so.
Last week, the North reiterated that the deadline is drawing closer, saying that it was "entirely" up to the US what "Christmas gift" it wants to get, putting pressure on Washington to take first action in making concessions.
( With inputs from IANS )