US Defence Secretary James Mattis has reassured the leader of South Korea that the alliance between the two nations remains strong.
Mr Mattis said the relationship would only be strengthened in the face of threats from North Korea.
It comes after President Donald Trump accused South Korea and Japan of not paying enough for US military support.
The visit to Seoul is the first foreign trip by a senior official in the Trump administration.
Mr Mattis took the opportunity to commit to the continuation of US support through previously agreed security deals.
During his campaign last year, Mr Trump threatened to withdraw US forces from South Korea and Japan if they failed to increase their financial support to US military operations.
He also suggested that the two countries could be allowed to arm themselves with nuclear weapons, an idea that was rejected by both nations.
Mr Trump has also said that he is willing to talk to North Korean leader Kim Jong-un, contradicting longstanding US, South Korean and Japanese policy.
Join GhanaStar.com to receive daily email alerts of breaking news in Ghana. GhanaStar.com is your source for all Ghana News. Get the latest Ghana news, breaking news, sports, politics, entertainment and more about Ghana, Africa and beyond.