South Korea sold 3.6 million tons of steel products to the US last year, making it the No. 3 steel exporter following Canada and Brazil, according to the Department of Commerce.

The announcement came as Seoul and Washington continue talks to renegotiate their free trade agreement. Trump has called it a bad deal that cost American jobs and widened the US trade deficit with South Korea.

South Korean officials, including the trade minister, have been in Washington in recent days to win an exemption from the tariffs.

They have cited the importance of maintaining a united front as they seek to resolve the issue of North Korea's nuclear weapons program.

Last week South Korean Foreign Minister Kang Kyung-wha said it was not helpful to have a trade row at a time when both Seoul and Washington are trying to make progress in efforts to denuclearize the North.

South Korean President Moon Jae-in and Trump are set to hold separate summits with North Korean leader Kim Jong-un this spring. (Yonhap)