Blinken, accompanied by Defence Secretary Lloyd Austin, met with their South Korean colleagues, Foreign Minister Chung Eui-yong and Defence Minister Suh Wook, to discuss cooperation on North Korean policies and reinvigorate the alliance.
The denuclearisation of the peninsula has been called the number one priority of the Seoul-Washington alliance. The sides agreed to continue working closely on a North Korean policy review, set to be finished in the next few weeks.
"We are committed to the denuclearisation of North Korea, reducing the broader threat the DPRK [North Korea] poses to the United States, and our allies and improving the lives of all Koreans, including the people of North Korea, who continue to suffer widespread and systematic abuses within the hands of the repressive government", Blinken said.
He noted that despite what Washington sees as Beijing's "consistent failure to uphold its commitments", China still plays a crucial role in resolving the nuclear issue due to its "unique" relationship with Pyongyang.
"Beijing has an interest, a clear self-interest in helping to pursue the denuclearisation of DPRK. Because it is a source of instability, it's a source of danger and obviously a threat to us and our partners, but China has a real interest in helping to deal with this", Blinken stressed.
Washington also highly regards the trilateral cooperation between the US, South Korea, and Japan, with Blinken stressing its importance in the face of what the US sees as the growing threat from the North and China.
Earlier on Thursday, North Korean first vice foreign minister Choe Son Hui said Pyongyang will continue to ignore any contact from the US until Washington ends "hostile policies" toward North Korea.
Blinken and Austin arrived in Seoul on Wednesday after a three-day visit to Japan, marking an end to a week-long campaign aimed at highlighting the Biden administration's efforts to strengthen relations with its allies and partners in the region. Blinken will join National Security Adviser Jake Sullivan later on Thursday for a first face-to-face meeting with their Chinese counterparts in Anchorage, Alaska.