A top U.S. diplomat for East Asia affairs arrived in South Korea on Tuesday, kicking off a three-day trip during which time he will discuss bilateral security and diplomatic issues.

Arriving at Incheon International Airport from Manila, Assistant Secretary of State for East Asian and Pacific Affairs David Stilwell told reporters that the relationship between the U.S. and South Korea is vital to stability and prosperity in the region. 

He added that over the years, he has watched that relationship “grow and thrive and expand” as the Korean side gets stronger and more able to provide. He said he hopes that trend will continue. 

Stilwell did not comment on the current trade row between Seoul and Tokyo, saying only he will be prepared to talk about the issue Wednesday.

He will reportedly pay a visit to the presidential office before meeting with Foreign Minister Kang Kyung-wha on Wednesday. He will also meet his South Korean counterpart from the Foreign Ministry and top nuclear envoy Lee Do-hoon. 

Stilwell's visit comes at a time of heightened tensions between the U.S.' two Northeast Asian allies following Japan’s introduction of export controls on key high-tech materials to South Korea.