A group of five small businesses on Monday sued President Donald Trump, seeking to block new tariffs that he has imposed on foreign imports in recent weeks.

President Trump’s “Liberation Day” tariffs came under their first major legal challenge Monday, brought by a libertarian public-interest firm that argues the president overstepped his authority. Trump’s April 2 announcement imposed a baseline 10 percent tariff on imports and targeted dozens of countries with higher “reciprocal” tariffs.