Yoon from South Korea will visit the US before the Biden summit

South Korea's President Yoon Suk Yeol flew to Washington Monday for a six-day state visit, as the allies move to bulk up military cooperation over North Korea's expanding nuclear threats. Pyongyang has conducted another record-breaking string of sanctions-defying launches this year, including test-firing the country's first solid-fuel ballistic missile. In response, Yoon has pulled South Korea closer to long-standing ally Washington, and the trip has a packed schedule including a summit with US President Joe Biden on Wednesday. Analysts say the two leaders have some "uncomfortable" topics to discuss at their summit. The trip comes as Yoon grapples with the South's increasingly nervous public about the US commitment to so-called extended deterrence, where US assets serve to prevent attacks on allies.

A majority of South Koreans now believe the country should develop its own nuclear weapons. Yoon has hinted that Seoul could pursue this option, as the US has shown its deterrence commitments at the alliance level. Yoon is likely to come under pressure to do more to help the US support Ukraine, as Washington looks to South Korea to help secure ammunition and weapons for Kyiv. Seoul is also mired in a diplomatic spat with Beijing after Yoon blamed recent tensions over Taiwan on "attempts to change the status quo by force". Yoon must be careful to avoid "unintentionally provoking" other countries like China and Russia during this trip, an editorial in the Joongang Ilbo newspaper said.