The President-elect announced a deal with the air conditioning manufacturer Carrier to keep jobs in the country
Donald Trump has warned companies considering leaving the US that they will face consequences if they move.
The President-elect is currently touring the Carrier air-conditioning factory in Indianapolis, Indiana, where he told workers that firms moving abroad would be "taxed very heavily" at the US border.
"Companies are not going to leave the United States any more without consequences. Not going to happen," he said.
"They can leave from state to state, and negotiate deals with different states, but leaving the country will be very, very difficult."
Mr Trump's comments, his first major public remarks since winning the White House, came as he announced a deal with the air conditioning manufacturer to keep jobs in the country.
The billionaire made saving the plant a central promise of his campaign, and a deal was reached this week to keep 1,100 jobs there.
Indiana state officials have agreed to give United Technologies Corp $7 million worth of tax breaks over 10 years to encourage the company to keep jobs there.
However, hundreds more workers are still facing unemployment.
Mr Trump has also vowed to lower the country's business tax rate from 35% "hopefully down to 15%" and eliminate regulations, although any changes to the tax code would need to be approved by Congress.
More than 5 million manufacturing jobs have been wiped out across the US since 2000, with Indiana alone losing about 150,000 factory roles.