The warning by Kim Yo Jong came after South Korea resumed firing exercises near its tense land and sea borders with North Korea in the past two weeks.
The exercises were the first of their kind since South Korea suspended a 2018 agreement with the North aimed at easing front-line military tensions in June.
“The question is why the enemy kicked off such war drills near the border, suicidal hysteria, for which they will have to sustain terrible disaster,” Kim Yo Jong said in a statement carried by state media.
She accused South Korea’s conservative government of deliberately escalating tensions as a way to escape a domestic political crisis. She said the riskiness of the South Korean drills is clear to everyone as they happened amid “a touch-and-go situation” established after the U.S., South Korea and Japan recently held a new trilateral military exercise that North Korea views as a security threat.
“In case it is judged according to our criteria that they violated the sovereignty of (North Korea) and committed an act tantamount to a declaration of war, our armed forces will immediately carry out its mission and duty assigned by the (North Korean) constitution,” she said, without elaborating.
Later Monday, Koo Byoungsam, a spokesperson at South Korea’s Unification Ministry, described Kim’s statement as an attempt to trigger an internal divide in South Korea, saying that North Korea must first look at its own human rights violations and the international isolation caused by its nuclear program.
South Korea’s Defense Ministry separately said it will continue its live-fire drills as scheduled but didn’t say when and where new exercises are planned.
