The Ministry of National Defense headquarters in Yongsan, Seoul (Yonhap)
The Ministry of National Defense headquarters in Yongsan, Seoul (Yonhap)

The defense ministry on Tuesday expressed "grave concerns" over North Korea's escalation of inter-Korean border tensions with military threats and its criticism of South Korean military operations conducted in response to last month's mine blast that injured its soldiers.

"The Ministry of National Defense expresses grave concern over Kim Yo-jong's criticism of our military's legitimate operations conducted under the Armistice Agreement, as well as her escalation of tensions through military threats," it said in a statement.

"The warning broadcasts and warning shots conducted by our military near the Military Demarcation Line are legitimate and defensive measures intended to prevent North Korean troops from violating the MDL and to repel those that cross it," the ministry said.

In a commentary issued by state media Monday, Kim, the powerful sister of North Korean leader Kim Jong-un, threatened to deploy more weapons along the border and resume propaganda loudspeaker broadcasts, citing the South's numerous warning broadcasts and warning shots that she claimed has turned the border area "very unstable." (Yonhap)