President Yoon Suk Yeol speaks at a Cabinet meeting at the presidential office in Seoul on Tuesday. (Yonhap)

The office of President Yoon Suk Yeol is considering suspending a 2018 inter-Korean summit agreement if North Korea violates the South's territory again, officials said Thursday.

The Pyongyang Joint Declaration was signed by then President Moon Jae-in and North Korean leader Kim Jong-un after their September 2018 summit in Pyongyang.

The possibility of suspending it comes after Yoon instructed the presidential National Security Office on Wednesday to consider suspending a military tension reduction agreement, which was signed as an annex to the Pyongyang Joint Declaration, in the event the North carries out a provocation similar to its drone infiltration of South Korean airspace last week.

"We need to look into other agreements connected to the Sept. 19 military agreement," a key presidential official told Yonhap News Agency. "It's part of our sovereignty to invalidate inter-Korean agreements if circumstances change."

The military agreement calls for halting all hostile military activity between the Koreas and includes plans to turn the Demilitarized Zone into a peace zone.

North Korea has "explicitly" violated it 17 times, including 15 times starting in October, according to the presidential office.

The office is considering suspending both agreements because they are interlinked, with the Pyongyang Joint Declaration stating the two sides agreed to "fully abide by and faithfully implement" the military accord.

Under the Development of Inter-Korean Relations Act, the president can suspend all or parts of inter-Korean agreements "for a fixed specific period, when significant changes occur in inter-Korean relations or when it is deemed necessary for national security, maintenance of order or public welfare."

Suspending the agreements could lead to a resumption of loudspeaker broadcasts into the North, which typically included messages critical of the North Korean regime and K-pop music.

The government is also weighing whether to resume distribution of anti-Pyongyang leaflets across the border.

"If the Sept. 19 military agreement is suspended, our military can once again use anti-North Korea loudspeakers in the border areas," a government official said. (Yonhap)