BEIJING - China is "gravely concerned" over reports that four more launchers for the THAAD anti-missile system were brought into the Republic of Korea without its President Moon Jae-in being informed, Foreign Ministry spokeswoman Hua Chunying said in a news conference in Beijing on Wednesday.

Hua reiterated China's resolute opposition against the deployment of THAAD, saying the deployment will severely damage China's security interests and undermine the regional strategic balance.

In addition, the deployment "won't help achieving denuclearization of the Korean Peninsula and regional peace and stability, and runs counter to all parties' efforts to solve the issue through dialogue and consultation", Hua said, urging the United States and the ROK to cancel the deployment.

Hua was reacting as claims surfaced that the ROK's Defense Ministry "intentionally dropped" mentioning that four more launchers had been deployed for the THAAD in a report to President Moon Jae-in.

Moon has ordered a probe at the Defense Ministry, saying it was "very shocking" the launchers had been brought in without being reported to the new government or to the public, presidential Blue House spokesman Yoon Young-chan said on Tuesday.

"The Blue House has confirmed that the Defense Ministry intentionally dropped the introduction of four more launchers in its report," Yoon said.

Moon took office on May 10 without a transition period because a snap presidential election was held two months after his predecessor, Park Geun-hye, was ousted in a corruption scandal. Moon inherited his defense minister along with the rest of his cabinet from the previous administration.

The THAAD battery was initially deployed in March in the southeastern region of Seongju with just two of its maximum load of six launchers.

An earlier version of the Defense Ministry report specified the total number of launchers being prepared for deployment and the name of the US military base where the four were being kept, but the reference was removed in the final version delivered to the Blue House, Yoon said.

During his successful presidential campaign, Moon called for a parliamentary review of the THAAD system.

Reuters contributed to this story