WASHINGTON – American businesses are paying much more in tariffs than they did last year, due mainly to President Donald Trump's aggressive trade policies, according to an analysis by industry groups.

U.S. businesses shelled out $4.4 billion in tariffs in September, a surge of more than 50 percent from the same month a year ago, according to the groups, which are operating under a coalition called Tariffs Hurt the Heartland. The increase was largely driven by $1.4 billion in Trump administration tariffs on Chinese imports and foreign steel and aluminum, the group said.

"The historic rise in costs for American businesses, farmers and consumers is only the beginning," coalition spokesman Charles Boustany said in a statement. Boustany, a Republican, represented Louisiana in the House for over a decade.

The coalition worked with the Trade Partnership, a consulting firm, to calculate the cost of the tariffs using government data. The Trump administration has imposed tariffs on several fronts, including against long-standing economic allies. In March, the president announced new duties on all steel and aluminum imports, citing national security concerns. The measures cost U.S. companies about $545 million in September, the data show.

Even more costly were tariffs levied against China, which the administration has accused of stealing U.S. intellectual property. Those tariffs accounted for $800 million in September, even though the bulk didn't take effect until the end of the month.