A senior official at the U.S. State Department has stressed the importance of cooperation between South Korea and Japan. 

Sung Kim, acting assistant secretary of state for East Asian and Pacific affairs, said on Wednesday that cooperation between South Korea and Japan is more important to the U.S. than any other relationship. 

In a webinar hosted by the Center for Strategic and International Studies, a Washington-based think tank, Kim said that the Biden administration is committed to strengthening America's relationships, not only with its allies but those among allies.

He added that none are more important than Japan and South Korea.  

The senior diplomat then said that the U.S. will explore opportunities to expand cooperation in areas such as tackling COVID-19 and addressing climate change, and work together to reinvigorate trilateral cooperation on the North Korea challenge.