South Korean President Park Geun-hye visited with U.S. President Barack Obama this week and also addressed a joint session of Congress.
Both the United States and South Korea have expressed concern about the security situation on the Korean Peninsula following the February test of a nuclear device by North Korea.
North Korea said Friday that Park's visit was a sign she was trying to make the regional situation worse.
"It is a curtain-raiser to a dangerous war to invade (North Korea)," a government statement published by South Korea's Yonhap news agency said.
Park told U.S. lawmakers she was addressing the regional situation calmly but with a sense of resolve.
South Korean Unification Ministry spokesman Kim Hyung-suk questioned North Korea's latest rhetoric, describing it as overly confrontational.
North Korea also this week expressed frustration with U.S.-South Korean naval exercises in the Yellow Sea.