President Donald Trump said Friday he had authorized the doubling of tariffs on imports from Turkey, imposing a 20 percent duty on aluminum and 50 percent one on steel, as tensions mount between the two NATO allies over Ankara's imprisonment of an evangelical pastor and other diplomatic issues.

"I have just authorized a doubling of Tariffs on Steel and Aluminum with respect to Turkey as their currency, the Turkish Lira, slides rapidly downward against our very strong Dollar!" Trump said in an early morning post on Twitter. "Aluminum will now be 20 percent and Steel 50 percent. Our relations with Turkey are not good at this time!"