Pyongyang conducts live-fire drills close to its coast for the third time in a row as it threatens Seoul.
North Korea has threatened an immediate military strike against South Korea in response to any “provocation”.
Kim Yo Jong, the powerful sister and key ally of leader Kim Jong Un, made the threat on Sunday, as Pyongyang reportedly fired artillery shells near its border with South Korea for the third day in a row.
The remarks follow South Korean military reports that said the North had fired more than 60 artillery rounds on Saturday near their disputed maritime border.
A similar volley of more than 200 rounds was reported the previous day. North Korea fired more than 90 rounds on Sunday, according to the South.
“The North Korean military has been conducting the drills north of the South Korean front-line island of Yeonpyeong since about 4pm [07:00 GMT],” the South Korean Yonhap news agency reported, citing a military source.
Kim Yo Jong, one of the most powerful members of Kim Jong Un’s government, said in a statement carried by state news agency KCNA that the safety catch on the trigger of the Korean People’s Army (KPA) had already been slipped.
“As already declared, the KPA will launch an immediate military strike if the enemy makes even a slight provocation,” Kim said.
Although South Korea held its own fire drills in the sea on Friday in response to the artillery shells, Yonhap reported there was no plan to do so after Saturday’s events.
The drills on both sides of the border on Friday sparked warnings for residents of South Korean border islands to seek cover in bomb shelters, although there were no reports of shells crossing the maritime border.
In her statement on Sunday, Kim denied the artillery shell firings on Saturday and said the North had detonated explosives as a deception tactic.
South Korea’s military rejected Kim’s statement as low-level psychological warfare, urging North Korea to cease military activity that raises tension near the border.
Relations between the two Koreas are at their lowest points in decades after Kim Jong Un last year enshrined his country’s status as a nuclear power into the constitution and test-fired several advanced intercontinental ballistic missiles.
At Pyongyang’s yearend policy meetings, Kim threatened a nuclear attack on the South and called for a build-up of his country’s military arsenal before an armed conflict, which he warned could “break out any time”.