WASHINGTON, March 26 (Xinhua) -- A U.S. association representing the steel industry said it will appeal a recent ruling by a federal court upholding the constitutionality of President Donald Trump's move to impose tariffs on steel and aluminum imports from U.S. trading partners.

The American Institute for International Steel (AIIS) said in a statement Monday that they are "appealing immediately" the ruling made on the same day by the U.S. Court of International Trade (CIT) that upheld Trump's use of Section 232 of the Trade Expansion Act of 1962 to levy metal duties on national security grounds.

The AIIS and two of its member companies -- Texas-based Sim-Tex, a wholesaler of oil and gas pipe, and Kurt Orban Partners, an international steel trader based in California -- had filed lawsuit on June 27, 2018 to the CIT, challenging the constitutionality of the tariffs.

The group said Section 232 violates the constitutional prohibition against Congress delegating its legislative powers to the president because it lacks any "intelligible principle" to limit the discretion of the president.

It added that the national security concern is "expansively defined" by the decades-old legislation, which "allows the president to impose unlimited tariffs or create other trade barriers at his unfettered discretion."

A panel of three judges of the New York-based court concluded in a ruling that Section 232 met the "intelligible principle standard," citing the "FEA v. Algonquin SNG, Inc." case heard by the Supreme Court in 1976 that involved a presidential order to impose license fees on oil imports based on Section 232.

Judge Gary Katzmann wrote in an opinion piece after the ruling that he and his colleagues, relying largely on the 1976 Supreme Court decision, concluded that "the statute passes constitutional muster."

Questioning the appropriateness of sticking to the 1976 Supreme Court decision, Katzmann wrote, "While acknowledging the binding force of that decision, with the benefit of the fullness of time and the clarifying understanding borne of recent actions, I have grave doubts."

Katzmann said it is difficult to escape the conclusion that Section 232 has permitted the transfer of power to the president in violation of the separation of powers.

AIIS said it remains convinced of the same assertion. "We are appealing immediately in order to continue making that argument," it noted.