Republican leader Paul Ryan publicly split with Donald Trump on Monday over the president’s threat to impose tariffs on the US’s trading partners on steel and aluminium.

The House speaker became the most senior Republican to publicly distance himself from Trump’s tariffs, which have rattled stock markets worldwide and sparked threats of retaliation. “We are extremely worried about the consequences of a trade war and are urging the White House to not advance the plan,” AshLee Strong, Ryan’s spokeswoman said in a statement.

She said the tariffs plan threatened to jeopardize the impact of Trump’s recently introduced $1.5tn tax reforms.

Ryan’s split came shortly after Trump had doubled down on the tariff plan in a pair of tweets. The president reiterated his displeasure with trade deficits with Mexico and Canada, two of the US’s largest trading partners. Metals duties will only be removed on America’s neighbours to the north and south, he said, after a “new and fair” free trade agreement is signed.

Trump followed up with another tweet proclaiming: “To protect our Country we must protect American Steel! #AMERICA FIRST.”

Asked later about Ryan’s comments, Trump replied: “No, we’re not backing down. Mexico is … we’ve had a very bad deal with Mexico, a very bad deal with Canada. It’s called Nafta. Our factories have left our country. Our jobs have left our country. For many years Nafta has been a disaster.”

He added: “We are renegotiating Nafta, as I said I would. And if we don’t make a deal, I’ll terminate Nafta. But if I do make a deal which is fair to the workers and to the American people, that would be, I would imagine, one of the points that we’ll negotiate. It will be tariffs on steel for Canada and for Mexico.”

Trump has long attacked Nafta, the North American Free Trade Agreement. The latest round of a nearly year-long renegotiation effort is concluding this week in Mexico City.

Trump also called on Canada to “treat our farmers much better” and Mexico to do “much more” on stopping the flow of illegal drugs into the US.

The White House trade adviser, Peter Navarro, earlier rejected criticism of the planned tariffs amid concerns they may kick off a trade war, telling Fox and Friends: “There are virtually no costs here...

“If you put a 10% tariff on aluminum, it’s a cent and a half on a six pack of beer and it’s $25,000 on a $330m [Boeing 777].”

Reacting to repeated threats that the US could pull out of Nafta if partner countries do not agree on mechanisms designed to balance trade, Mexico has warned that it is better prepared to handle a bloc breakup than the US.

Mexico’s economics ministry noted the country has already made preparations to widen its trade portfolio and strengthen its commercial relationships with Europe, Brazil, Japan and China. Mexico currently has free trade agreements with 46 countries, compared with the 20 held by the US.

Last year, Brazil, the EU and Japan increased exports to Mexico by 11.3%, 13.3% and 4.9% respectively, according to Mexican government figures.

“It’s very simple: if today I’m the top buyer of yellow corn, rice, chicken, pork from the US, I need to open a space for trade with Brazil and Argentina so that at the table people reaize that we have options,” Mexico’s economic secretary, Ildefonso Guajardo, warned.

The ministry also warned that if the US withdraws from Nafta, tariffs on exports will increase and US businesses will lose market share, which could translate into lower wages and possible job losses in the US as well as higher prices on consumer goods.



His comments echoed those of some US economists.

A report on Friday from the Center for Automotive Research noted that “American consumers would buy fewer vehicles if prices were to rise at a rate commensurate with materials cost share and the tariff impact”.

The list of US consumer goods that could cost more as a result of aluminium and steel tariffs is long, affecting everything from canned food and beverages to household appliances and cars.

Also of concern is the potential for retaliatory tariffs, and a possible trade war. Jean-Claude Juncker, the president of the European commission, told reporters on Friday that he “will not sit idly while our industry is hit with unfair measures that put thousands of European jobs at risk”. Juncker threatened tariffs on US exports like Harley-Davidson motorcycles, Kentucky bourbon and Levi’s jeans.

Amid speculation that Trump may bow to pressure and amend his tariff plan before it is put into effect in the coming weeks, Navarro reiterated that there would be no country exemptions on the tariffs of 25% on steel and the 10% on aluminum.

“Firm line in the sand,” he said.