A senior U.S. official says an unexpected meeting this week between the leaders of South Korea and Japan was an "encouraging sign" that the Asian U.S. allies are on track to improve a relationship strained by deep rows over trade and history.

U.S. Assistant Secretary of State for East Asia and the Pacific Affairs David Stilwell spoke Wednesday after meeting South Korean Foreign Minister Kang Kyung-hwa in Seoul.

Stilwell's visit comes weeks before the expiration of a military intelligence-sharing agreement between South Korea and Japan that Seoul has threatened to end in retaliation for Tokyo's moves to tighten controls on exports to its neighbor.

A poster with an image of Japanese Prime Minister Shinzo Abe denouncing Japan's trade restrictions is seen on a street in Seoul, South Korea, Tuesday, Nov. 5, 2019. South Korean President Moon Jae-in and Japanese Prime Minister Shinzo Abe met one-on-one Monday for the first time in more than a year and called for more dialogue between the countries to settle a deep dispute over trade and history. The sign reads "Our boycott is not over." (AP PhotoAhn Young-joon)

A poster with an image of Japanese Prime Minister Shinzo Abe denouncing Japan's trade restrictions is seen on a street in Seoul, South Korea, Tuesday, Nov. 5, 2019. South Korean President Moon Jae-in and Japanese Prime Minister Shinzo Abe met one-on-one Monday for the first time in more than a year and called for more dialogue between the countries to settle a deep dispute over trade and history. The sign reads "Our boycott is not over." (AP PhotoAhn Young-joon)

Following an angry reaction from the Trump administration, Seoul said it could reconsider if Japan relists South Korea as a favored trade partner.

Banners calling for a boycott of Japanese products are displayed inside the Suyu market in Seoul, South Korea, Tuesday, Nov. 5, 2019. South Korean President Moon Jae-in and Japanese Prime Minister Shinzo Abe met one-on-one Monday for the first time in more than a year and called for more dialogue between the countries to settle a deep dispute over trade and history. The sign reads: "The Suyu market will be the vanguard of the anti-Japanese boycott." (AP PhotoAhn Young-joon)

Banners calling for a boycott of Japanese products are displayed inside the Suyu market in Seoul, South Korea, Tuesday, Nov. 5, 2019. South Korean President Moon Jae-in and Japanese Prime Minister Shinzo Abe met one-on-one Monday for the first time in more than a year and called for more dialogue between the countries to settle a deep dispute over trade and history. The sign reads: "The Suyu market will be the vanguard of the anti-Japanese boycott." (AP PhotoAhn Young-joon)