WASHINGTON, March 31 (Reuters) - Two Michigan business

groups urged President Donald Trump to halt plans to impose

sweeping 25% tariffs on imported vehicles and parts, saying it

would lead to dramatic price hikes, supply-chain disruptions and

pain in the auto-heavy state.

"The increased costs would cause significant disruption

throughout the supply chain and, perhaps most importantly, lead

to significant price increases to the cost to American consumers

for vehicles," the Detroit Regional Chamber and MichAuto, an

automotive and mobility association, said in a letter.

"In Michigan, where one in five jobs is automotive-related,

the pain felt by working-class citizens will be profound." The

auto sector contributes about  $300 billion  to Michigan's

economy annually, according to the Detroit Regional Chamber.

Trump last week followed through on weeks of threats for new

tariffs on imported cars, saying a 25% import tax on vehicles

not built in the U.S. would kick in on April 3 - on top of

previous duties. He could also add new duties on autos as part

of sweeping new tariffs he will announce Wednesday.

The groups said that the tariffs will damage the state's

automotive industry and economy, noting there are more than

1,000 automotive suppliers based in Michigan.

"The tariff policies proposed will increase prices, drive

down consumer demand, and therefore, lower the profitability of

our companies, directly impacting the hardworking Americans who

assemble the iconic vehicles," the letter added.

Higher new vehicle prices could prompt some owners to hold

on to old vehicles longer, raising used car prices. "These

increased vehicle costs will be disproportionately borne by

working-class and middle-class families," the letter said.

In response, White House spokesperson Kush Desai noted

automakers like Hyundai have announced new

investments in the United States and argued those investments

and Trump's call for a new tax deduction on interest on car

loans "will continue to drive historic manufacturing and job

growth."

A group representing General Motors ( GM ), Ford,

Toyota ( TM ), Stellantis ( STLA ) and others warned the

tariffs will hike vehicle costs. Hyundai told auto

dealers they may need to adjust prices if the tariffs take

effect.