President Donald Trump's proposed tariffs could lead to the loss of jobs in the manufacturing industry, Republican Rep. Jackie Walorski told CNBC on Monday.

Employees right now are looking at "jobs potentially leaving, orders in the queue [and] expansion plans downsized. There is a cost to this," said Walorski, who represents the second district of Indiana.

"All I'm saying is let's be balanced."

Last week, the president announced the U.S. would enact tariffs of 25 percent on steel and 10 percent on aluminum. Steel manufacturers largely cheered the move.

However, Walorski said the CEOs of recreational vehicle, boating and trailer manufacturers in her district are worried. They all use steel in their products.

"I ran into a CEO at the airport this morning who is already getting a 20 percent increase in the material from these domestic companies here because they know tariffs are coming and there's no choice," she said in an interview with "Power Lunch."

"This industry is on an incline of momentous growth," she added. "I don't want to stop that growth."

Walorski said as much in a letter to Trump last week.

"Early feedback from manufacturers in my district has me worried that immediate, blanket tariffs could reverse the economic recovery and return of manufacturing jobs to northern Indiana," she wrote.

She's not the only Republican expressing concern.

On Monday, House Speaker Paul Ryan's spokesperson said, "We are extremely worried about the consequences of a trade war and are urging the White House to not advance with this plan."

Trump responded by saying, "We aren't backing down."

However, he did signal that he may drop tariffs for Canada and Mexico if they can renegotiate a new NAFTA deal with the U.S.

A Republican source told CNBC that congressional leaders have not ruled potential action if Trump follows through on his plan.

— CNBC's Kevin Breuninger and Thomas Franck contributed to this report.