North Korea reportedly detonated explosives before and after an artillery drill near the western maritime border on Saturday.

According to a source within the South Korean military on Monday, North Korea fired some 60 shells into waters northwest of South Korea's Yeonpyeong Island on Saturday bookended by a total of around ten explosive detonations.

The source said that such an act is the first of its kind and was intended to deceive the South Korean military.

On Sunday evening, the North's state-run Korean Central Television broadcast footage showing some 20 soldiers detonating explosives in a box in a field.

In a statement carried by the regime's Korean Central News Agency on Sunday, Kim Yo-jong, the powerful sister of leader Kim Jong-un, said that the North conducted a deceptive operation by detonating explosives simulating the sound of its coastal artillery the previous day.

Kim claimed, however, that not a single artillery shell was fired into the maritime buffer zone.