U.S.-South Korea relations strained as Kim Jong Un's sister insults Biden and nuclear-armed subs are sent to South Korea.

Kim Yo Jong, the sister of North Korea's leader, has criticized the US-South Korean agreement to intensify nuclear deterrence, calling it "extreme" and "hostile." She also insulted President Joe Biden, calling him senile and "too miscalculating and irresponsibly brave." North Korea has test-fired around 100 missiles since the start of 2022, and Kim Jong Un is expected to continue to accelerate the country's campaign to cement its status as a nuclear power. The US and South Korea announced new nuclear deterrence efforts, including periodically docking US nuclear-armed submarines in South Korea and improving information sharing on nuclear and strategic weapons operation plans.