President Donald Trump speaks during a meeting with steel and aluminum executives in the Cabinet Room of the White House, March 1, 2018, in Washington.(AP/Evan Vucci)

US President Donald Trump's imposition of a 25 percent tariff on steel and aluminum imports is facing legal challenge at home. The American Institute for International Steel (AIIS), and its two members, filed a lawsuit against the decision on Wednesday.

AIIS complained that even though many of its member companies do not pay the tariffs directly, they still bear the impact due to decreasing imports and rising costs.

The lawsuit, filed in the US Court of International Trade in New York, requested the court declare the tariffs triggered by the Section 232 investigation unconstitutional.

The Section 232 of the 1962 Trade Expansion Act empowers the president to impose tariffs on imports that could pose a national security risk.