The U.S. Commerce Department is slapping heavy duties on South Korean and Taiwanese steel products shipped from Vietnam.

The department said in a statement Tuesday that it would impose duties of up to 456 percent on certain steel products produced in South Korea and Taiwan that are then shipped to Vietnam for minor processing before being exported to the United States.

The department said it found corrosion-resistant steel products and cold-rolled steel produced in Vietnam using South Korean or Taiwanese-origin substrate had circumvented U.S. anti-dumping and anti-subsidy duties. 

Duties on these products directly shipped from South Korea and Taiwan were imposed in December 2015 and February 2016, respectively. 

The department said since those dates through April 2019, shipments of corrosion-resistant steel products and cold-rolled steel from Vietnam to the U.S. had increased by 332 percent and 916 percent compared to earlier time periods.

It said the department inquiry was initiated at the request of related steel producers in the U.S.