President-elect Donald Trump on Sunday issued a dramatic warning to companies that they would face “retribution” in the form of tariffs if they move American jobs overseas, setting up a collision with corporate America and the free-market wing of the Republican Party.

In a string of early-morning tweets, Trump said he intends to keep jobs in the United States by lowering taxes for companies and slashing regulations, two key components of his economic agenda. But he also warned that companies that send jobs offshore would face a 35 percent tariff on goods sold back to the United States.

“Any business that leaves our country for another country, fires its employees, builds a new factory or plant in the other country, and then thinks it will sell its product back into the U.S. … without retribution or consequence, is WRONG!” Trump wrote on Twitter.

The threat marked perhaps the clearest sign yet since the election that Trump has not abandoned the controversial economic positions he adopted during the campaign. In addition to vowing to hit American companies with severe consequences if they imperil American jobs as a candidate, he pledged to tear up trade agreements and tag products from countries such as China and Mexico with tariffs if those nations continue to take American jobs.

The comments set up a clash with Republicans who have long argued in favor of free trade and against excessive intrusion by government into the affairs of businesses.

Sen. Ben Sasse, R-Neb., a frequent Trump critic, argued that a 35 percent tariff would be passed along to American consumers in the form of higher prices.

“Pres-Elect Trump means well. But won’t his 35% tariff idea raise prices on American families? How would it not be a new 35% tax on families?” Sasse wrote on Twitter.

A conservative advocacy group, the Club for Growth, said that it favors Trump’s proposals on tax and regulatory changes but warned of the consequences of cutting off trade.

“We think it’s bad economic policy. It’ll cost more American jobs than it saves” said former Indiana congressman David McIntosh, the head of the Club for Growth.

“Therefore it needs to be stopped.”

Trump’s threat Sunday also put American companies in an extraordinarily difficult position. Offshoring has been a key element of corporate America’s strategy in recent decades, and major lobbying groups have been defenders of trade agreements. But groups stood nearly silent on Sunday, potentially worried about drawing the wrath of the president-elect.

The U.S. Chamber of Commerce, the nation’s largest business lobby, declined to directly respond to Trump’s comments but signaled that it has not budged in its opposition to tariffs.

“We are not going to comment on Trump’s comments directly, but in general, the Chamber has always called for pro-growth policies that help American companies succeed globally and welcome foreign investment within our borders,” said Blair Latoff Holmes, a spokeswoman for the group.

She pointed to a recent Fox Business Network interview in which the Chamber’s chief economist said that tariffs are “self-destructive.”

Last week, Trump made clear he would intervene in specific situations in which companies are considering moving work overseas. Last week he traveled to an Indiana factory owned by furnace and air-conditioner manufacturer Carrier to champion a deal to keep about 800 jobs in the United States. To much criticism, Carrier had planned to move them to Mexico.

On Sunday, Vice President-elect Mike Pence said that Trump would continue the extraordinary interventions, working on deals with such companies “on a day-by-day basis.”

Although Trump would be able to follow through on some of his threats without congressional approval – for example, declaring China a currency manipulator and launching a renegotiation of the North American Free Trade Agreement – it’s not clear whether he could penalize companies broadly for moving jobs overseas without congressional authorization.

Gary Clyde Hufbauer, a senior fellow at the Peterson Institute for International Economics, a think tank that regularly supports proposed trade deals, predicted that Trump would face legal obstacles if he tries to impose tariffs on individual companies unilaterally.

“This would be, in my way of thinking, a real intrusion of congressional powers over foreign commerce,” Hufbauer said.

“We’ve never had this kind of policy before, so he’s on novel ground.”