The top U.S. diplomat for East Asia met with Japanese officials on Friday to discuss North Korea and other major regional affairs.

David Stilwell, the U.S. assistant secretary of state for East Asian and Pacific affairs, is on his first overseas trip since assuming his current post on June 20.

He met separately with Japanese Vice Foreign Minister Takeo Akiba, Kazuhiro Suzuki who heads the Foreign Ministry's North American Affairs Bureau, and Kenji Kanasugi, head of the Asian and Oceanian Affairs Bureau.

They agreed in the talks to step up cooperation for a free and open Indo-Pacific region, as well as to work together toward the denuclearization of North Korea, according to the Japanese ministry.

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The visit came after U.S. President Donald Trump held a surprise meeting with North Korean leader Kim Jong Un late last month at the demilitarized zone between North and South Korea.

Another issue they are likely to have discussed is heightened tensions between the United States and Iran over a 2015 nuclear deal and attacks on oil tankers near the Strait of Hormuz.

They did not raise recent comments by Trump pressuring Japan to correct what he sees as an "unfair" security alliance, a Japanese official said.

A retired Air Force brigadier general, Stilwell is slated to make a stop in Aomori Prefecture, where he previously commanded Misawa Air Base, before departing Sunday to travel to the Philippines, South Korea and Thailand.