Trump: German car firms should become American

US Presidential candidate Donald Trump is wooing international companies to build factories in the United States with tax promises - including German car manufacturers.

"I want German car companies to become American car companies," the Republican nominee and former president told a Savannah campaign rally on Tuesday in the battleground state of Georgia.

If he wins the presidential election on November 5, he will make every large company an offer, the 78-year-old continued.

"I will give you the lowest taxes, the lowest energy costs and the lowest regulatory burden and free access to the best and biggest market on the planet, but only if you make your product here in America," he said.

The prerequisite is that the companies employ US workers.

"If you don’t make your product here, then you will have to pay a tariff, a very substantial tariff, when you send your product into the United States," Trump added.

Numerous US economists have criticized Trump's tariff idea, saying it amounts to a tax on consumers, as history shows that tarifs are typically passed on to the end user.

Trump also repeated his claim that Germany had gone back to coal-fired power plants after failing to phase out fossil fuels. But the German Foreign Office said coal will be off the grid by 2038 at the latest.