SEOUL, April 18 (Reuters) - Finance chiefs of the United States, South Korea and Japan on Wednesday acknowledged concerns regarding recent declines of the Korean won and the Japanese yen and agreed to work closely on forex market developments, South Korea's finance ministry said.

In their first trilateral meeting in Washington DC, they also condemned Russia's arms trade with North Korea and reaffirmed their commitment to coordinate sanctions imposed on Russia for its war against Ukraine, according to a statement from South Korea's finance ministry. (Reporting by Cynthia Kim; Editing by Alex Richardson)