FRANKFURT (Reuters) - Bosses of German companies including engineering group Siemens SIEGn.DE and carmaker BMW BMWG.DE will travel with Chancellor Angela Merkel to meet U.S. President Donald Trump this week, sources familiar with the matter told Reuters.

Germany's Chancellor Angela Merkel briefs the media during a European Union leaders summit in Brussels, Belgium March 9, 2017. REUTERS/Francois Lenoir

Faced with Trump’s “America First” policy and threats to impose tariffs on imported goods, the captains of industry will stress how many U.S. jobs are tied to “Deutschland AG”.

Trains-to-turbines group Siemens employs more than 50,000 people in the United States, its single biggest market, where it makes 21 percent of its total revenue, while BMW’s South Carolina plant is its largest factory anywhere in the world.

Trump will meet Merkel, Europe’s longest-serving leader, for the first time on Tuesday in Washington.

Merkel told business leaders in Munich on Monday that free trade was important for both countries, while a German government spokesman confirmed at a press conference that the two leaders would also meet with German business executives.

German chancellors have a long tradition of taking groups of business leaders along with them on trips to important countries. The other business leader accompanying Merkel will be the chief executive of ball-bearings maker Schaeffler SHA_p.DE.

The three chief executives will cross the Atlantic for a single scheduled meeting of less than an hour with Trump. They will brief the president on the German practice of training workers on the job while also sending them to classes at a vocational school to obtain formal qualifications.

Such training is traditionally offered by large German companies both at home and in their foreign operations, and is particularly prized in emerging economies, where it helps German corporations win business.

Sources of tension between Berlin and the new U.S. administration include an accusation by a senior Trump adviser that Germany profits unfairly from a weak euro, and Trump’s threat to impose 35 percent tariffs on imported vehicles.

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The United States is Germany’s biggest trading partner, buying German goods and services worth 107 billion euros ($114 billion) last year while exporting just 58 billion euros’ worth in return.

“The accusations of President Donald Trump and his advisers are plucked out of thin air,” the president of Germany’s VDMA engineering industry association, Carl Martin Welcker, said in a statement on Monday.

He said 81,000 people were employed in German-owned engineering firms in the United States with almost 30 billion euros in total revenue, while German export successes were linked to the high quality of goods, not foreign-exchange effects.

As part of a bid to bring jobs to America, Trump has urged carmakers to build more cars in the United States and discouraged them from investing in Mexico, where German and other carmakers have big plants.

Trump’s order banning citizens of some majority-Muslim countries from entering the United States, and a threat to tear up the NAFTA free trade deal between the United States, Mexico and Canada, have also unnerved business leaders.

Siemens chief executive Joe Kaeser expressed concern last month about developments in the United States since Trump took office, saying: “The new American president has a style that’s different from what we’re accustomed to. It worries us, what we see.”

BMW’s Chief Executive Harald Krueger said last week that introducing protectionist measures and tariffs would not be good for the United States.

The carmaker is expanding its plant in Spartanburg, South Carolina, to have a capacity of 450,000 vehicles, with 70 percent for export.

It is also building a new plant in Mexico, where it plans to invest $2.2 billion by 2019. Mexico’s lower labor costs and unique free trade position mean it now accounts for a fifth of all vehicle production in North America.

“America profits from free trade. We are supporters of free trade and not of protectionism,” Krueger told reporters at the Geneva auto show.