North Korea has continued to fire shells near the western maritime border area for the third consecutive day since Friday, despite South Korea's repeated calls for an immediate cessation of such military action defying the Sept. 19, 2018, inter-Korean military agreement.

The North Korean military fired around 90 shells north of South Korea's front-line island of Yeonpyeongdo from around 4 p.m. to 5:10 p.m. local time, according to South Korea's Joint Chiefs of Staff.

"We issue a grave warning against North Korea's continued artillery firing into buffer zones, which threatens peace on the Korean Peninsula and escalates tensions and we strongly urge for immediate cessation," the JCS said in a statement.

"Our military is closely monitoring expected provocations from North Korea as general elections approach and maintains a full readiness posture. In the event of provocation, we will respond ... overwhelmingly and decisively."

There were no North Korean artillery shells reported south of the Northern Limit Line or NLL in the West Sea -- which serves as the de facto inter-Korean maritime border -- and no casualties have been reported on the South Korean side, a South Korean military source who wished to remain anonymous confirmed to The Korea Herald.

The South Korean military has no plans to conduct tit-for-tat firing in response, the source added.

The North Korean military unleashed about 200 artillery shells from north of the South Korean front-line islands of Yeonpyeongdo and Baengnyeongdo on Friday morning, according to South Korea's JCS. The South Korean military initiated tit-for-tat live-fire drills in response to the shell firing which prompted residents on the islands to evacuate their homes and take shelter elsewhere.

The North Korean military fired around 60 rounds of shells, including artillery and multiple rocket launchers, from the coastal artillery bases northwest of Yeonpyeongdo from 4 to 5 p.m. on Saturday, according to South Korea’s Joint Chiefs of Staff.

Some artillery shells fired by North Korea on Friday and Saturday landed in the waters north of the NLL, but within the designated buffer zones. The buffer zones were mutually agreed upon by both Koreas as part of the September 19 military agreement, covering both the West Sea and East Sea.

They were the first shells fired by the North Korean military to fall within the maritime buffer zone since December 2022.

However, North Korea on Sunday denied the South Korean military’s announcement about artillery firing near the inter-Korean western maritime border, asserting that it did not launch any artillery shells on Saturday.

Kim Yo-jong, deputy department director of the Publicity and Information Department of North Korea's Workers' Party of Korea and influential sister of North Korean leader Kim Jong-un, asserted in a press statement that the North Korean military carried out 60 detonations of simulated explosive charges mimicking the firing of 130-millimeter coastal artillery.

"The military thugs of the Republic of Korea took the bait that we threw," Kim claimed in the Korean-language statement.

The JCS on Sunday dismissed Kim's statement as "vulgar instigation and a North Korean cliche, aimed at undermining the trust of the military and sowing internal conflicts within South Korea."

"Kim Yo-jong's statement amounts to nothing more than a rudimentary form of psychological warfare directed at undermining confidence in our military's detection capabilities," the JCS said. "We strongly warn against North Korea's military activities that intensify tensions along the border and urge for their immediate cessation."

North Korea has also continued to refute the announcements by the South Korean military. The General Staff of the Korean People's Army on Friday claimed that the "direction of naval live-shell firing doesn't have even an indirect effect" on Yeonpyeongdo and Baengnyeongdo in a statement.