The US President has announced a doubling of tariffs on steel and aluminium imported from Turkey.
Donald Trump took to Twitter to announce the move, suggesting US relations with Turkey "are not good at this time".
The decision means aluminum will now be hit with a 20% tariff, and 50% for steel.
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! Aluminum will now be 20% and Steel 50%. Our relations with Turkey are not good at this time!
— Donald J. Trump (@realDonaldTrump) August 10, 2018
It comes as the Turkish lira falls to a new low against the US dollar amid an escalating 'economic war' between the two countries.
The Associated Press reports that Turkish President Recep Tayyip Erdogan has urged citizens to convert their foreign currency into local lira.
He noted: "This is a domestic and national struggle,"
The US and Turkish governments are also in a dispute that has broken out due to Turkey holding a US evangelical pastor named Andrew Brunson on terror charges.
Brunson is accused of supporting a movement that the Turkish government has blamed for an attempted coup in 2016.
US officials have called for his release.
The Trump administration provoked fears of a trade war earlier this year when they announced tariffs on steel and aluminum imports, including on many of its allies.
It prompted retaliatory measures from the likes of the European Union and Canada.
However, EU leaders and President Trump have since reached an agreement "to work together towards zero tariffs" on goods.
Earlier this week, the Trump administration's trade war with China further escalated with the confirmation that a second tranche of tariffs - affecting $16bn of imports - would come into force later this month.
China responded by publishing its own list of US goods set to be hit with additional duties, with Chinese authorities warning they will take the "necessary counter-measures".