Apple Inc. (AAPL.O) Chief Executive Officer Tim Cook said tariffs show up as a “tax on the consumer” that result in lower economic growth and can sometimes can cause unintended consequences.

Tariffs are not the approach to modernize trade relations in the way that’s needed in some cases, Cook said in response to an analyst’s question on Apple’s earnings call. He’s optimistic that the U.S.-China trade tensions will be sorted out because of the “inescapable mutuality” of the world’s two largest economies.

Cook said no Apple products were directly affected by the tariffs implemented by the Trump administration so far.