President Donald Trump said he has an “easy solution” to Apple’s concerns about rising prices as a result of his trade war with China. The company should simply switch its manufacturing the United States, according to the president. “Apple prices may increase because of the massive Tariffs we may be imposing on China—but there is an easy solution where there would be ZERO tax, and indeed a tax incentive,” Trump wrote on Twitter Saturday. “Make your products in the United States instead of China. Start building new plants now.”

The president’s tweet came shortly after Apple sent a letter to the U.S. Trade Representative saying the proposed tariffs on Chinese goods would affect numerous Apple products, including its watch and charging cables. “Our concern with these tariffs is that the U.S. will be hardest hit, and that will result in lower U.S. growth and competitiveness and higher prices for U.S. consumers,” the company said.

Trump warned on Friday he was ready to step up the trade war with China by slapping tariffs on an additional $267 billion in goods, which would be in addition to the $200 billion in imports his administration is already considering. “The $200 billion we’re talking about could take place very soon,” Trump said. “To a certain extent, it’s going to be up to China.” That was seen as a sign that there could also be the possibility of a negotiated solution to the trade war. “I hate to say that, but behind that, there’s another $267 billion ready to go on short notice if I want. That totally changes the equation,” Trump told reporters on Air Force One.

The latest talk on tariffs comes as China’s trade surplus with the United States rose to a record in August. The surplus hit $31.05 billion in August, an increase from the $28.09 billion in July, according to official data. That is bound to raise tensions considering Trump frequently points to the surplus as evidence that China is beating the United States on trade. Analysts, however, say that one of the reasons why the surplus has increased is because U.S. importers are rushing their orders to avoid being affected by tariffs later. “Over the first seven months of the year, we’ve been seeing many people front-load their orders to avoid the tariffs,” one analyst explained.