The United States on Monday expressed its continued commitment to strengthening ties with South Korea and Japan amid an escalating row between the Asian nations.

Tensions between Seoul and Tokyo have spiked since the Japanese government last week announced tightened controls on exports of high-tech materials to the neighboring country.

South Korea views the measure as retaliation for last year's Supreme Court rulings that ordered Japanese companies to compensate Korean victims of forced labor during Tokyo's 1910-45 colonial rule of the Korean Peninsula.

Japan insists that all such matters were settled under a 1965 treaty on normalizing bilateral ties. Citing the agreement, Japanese Prime Minister Shinzo Abe has also called into question South Korea's compliance with United Nations Security Council sanctions against North Korea.

"As an ally and friend to both Japan and the Republic of Korea, the United States believes that it is critical to ensure strong and close relationships between and among our three countries in the face of shared regional challenges, including those posed by the DPRK, as well as our other priorities in the Indo-Pacific and around the world," a State Department spokesperson told Yonhap News Agency, referring to North Korea by its official name, the Democratic People's Republic of Korea.

"The United States is committed to strengthening further our trilateral cooperation with Japan and the Republic of Korea. We remain unified in pressuring North Korea to denuclearize."

The US has largely stayed out of the South Korea-Japan dispute despite the need to jointly address North Korea's nuclear threat and China's economic and military rise.

"The United States always pursues ways to strengthen relations between and among our three countries, both publicly and behind the scenes," the spokesperson said. (Yonhap)