North Korea opposes war, but if South Korea chooses military confrontation or makes a preemptive strike, then the North’s nuclear forces will have to attack, the powerful sister of leader Kim Jong Un said on Tuesday.

Kim Yo Jong, a senior official in the government and ruling party, said it was a “very big mistake” for South Korea’s minister of defense to make recent remarks discussing a preemptive attack on the North, state news agency KCNA reported.