President Donald Trump warned Friday that he would snub Apple's requests for tariff exemptions on device components imported from China, as he put pressure on the tech company to shift production to the United States.

"Apple will not be given Tariff wavers, or relief, for Mac Pro parts that are made in China. Make them in the USA, no Tariffs!" Trump said on Twitter.

Later, Trump told reporters that he wanted Apple to make the parts in the United States.

"When I heard they were going to build in China, I said when you send your product to the United States, we're going to tariff you."

Last week, Apple filed a request with the US trade representative, saying certain components for its $6,000 Mac Pro desktop computer could only be sourced from China and should be exempt from US tariffs.

The move comes amid frictions between the two economic powers, which are trying to restart failed negotiations on ending a trade war.

Trump has threatened to slap punitive tariffs on more goods to press Beijing to accept more imports and improve protections for US intellectual property.

Trump praised Apple CEO Tim Cook, saying he was someone "I have a lot of liking for and respect."

"We'll work it out. I think they'll announce they'll build a plant in Texas. If they do that, I'm starting to get very happy," he said.