China urged North Korea to "abide by the UNSC resolutions, stop any act that escalates security tensions on the Korean Peninsula, and join efforts to maintain peace and security in the region," he also added.

Around the midnight before Saturday, North Korea fired what it later announced was the Hwasong-14 ICBM. It soared to an altitude of around 3,700 kilometers and flew for more than 1,000 km before landing in the waters between Korea and Japan, according to the South Korean military.

The latest launch was an improvement from the North's another Hwasong-14 launch on July 4, which reached an altitude of about 2,800 km.     

In response to the latest provocation, President Moon Jae-in ordered additional launchers of the THAAD missile defense system be deployed, though a survey of its environmental impact should be continued as planned.

China strongly opposes the decision.

"China voices grave concerns over relevant actions by South Korea," the spokesman said. "Our stance to resolutely oppose the deployment of the U.S. THAAD system in South Korea has been consistent and clear."

South Korea and the U.S. announced in July last year they would install a THAAD battery to better counter the growing missile threat from North Korea.

China has been against the installation, saying the missile defense system and, in particular, its strong radar system could undercut its military capabilities.

Two THAAD launchers are in operation at a former golf course, some 300 kilometers southeast of Seoul, with the four others having been stored at a nearby U.S. military base. 

"Deploying the THAAD system will not address South Korea's security concerns, nor will it solve issues related to the Korean Peninsula, and will only complicate them," the spokesman said.

"What I want to emphasize is that the THAAD deployment in South Korea will seriously hurt the strategic balance in this region and undermine China's strategic security interests as well."