President Donald Trump said he authorized the doubling of existing steel and aluminum tariffs on imports from Turkey in response to a dramatic slide of more than 15% in the Turkish lira on Friday.

The lira USDTRY, +0.19% was last down 18.4% against the buck, according to Factset, marking its biggest loss since February 2001. One dollar bought 6.5731 lira, compared with 5.5426 late Thursday in New York.