Amid heightened tensions over North Korea's threats of retaliatory military action against South Korea, Seoul's Defense Ministry said on Sunday that the military is maintaining a staunch readiness posture to respond to all situations involving North Korea.

The ministry stressed that the September 19 inter-Korean military agreement should be fully implemented to establish peace on the Korean Peninsula and to prevent accidental clashes between the two nations.

The ministry also said that it is taking the current situation gravely, and closely watching the movement of North Korean troops.

The inter-Korean military accord was signed in 2018 during an inter-Korean summit in Pyongyang to ease military tensions on the Korean Peninsula.

Defense Minister Jeong Kyeong-doo reportedly held an emergency meeting of ministry officials earlier on Sunday to check the military readiness posture and discuss future responses to the North's recent threats.

The ministry's comment comes a day after Kim Yo-jong, the powerful sister of North Korean leader Kim Jong-un, warned of military actions in protest over Seoul's handling of leaflet campaigns by North Korean defectors.