North Korea said Saturday it has carried out "another crucial test" at its satellite launch site and the results will be used to strengthen its "reliable strategic nuclear deterrent", Yonhap news agency said.

The unspecified test took place from 10:41 p.m. to 10:48 p.m. on Friday at the Sohae Satellite Launching Ground, better known as the Dongchang-ri site, the North's official Korean Central News Agency said, reported the South Korean news outlet.

It is still not clear what was tested.

"The research successes being registered by us in defense science one after another recently will be applied to further bolstering up the reliable strategic nuclear deterrent of the Democratic People's Republic of Korea," the KCNA said.

"Our defense scientists were honored to receive warm congratulations from the Central Committee of the Workers' Party of Korea on the spot," it added.