United States President Donald Trump on Friday announced the imposition of higher tariffs on metal imports from Turkey, reported Reuters. He said his country’s relations with Turkey – an ally in the North Atlantic Treaty Organisation – were “not good at this time”.

Trump said he had authorised a doubling of duties on aluminium and steel imported from Turkey, to 20% and 50% respectively. According to the White House, Trump will employ a section of US law, which allows for tariffs on grounds of national security, claiming that excess of steel and aluminium harmed US companies and its economy.

The White House later clarified that the President’s announcement “authorised the preparation of documents”, reported AFP. The decision could take some time to come into effect.

The two countries have been embroiled in a spat over the detention of American pastor Andrew Brunson, the Syrian civil war, and other diplomatic matters. Earlier this month, the US imposed sanctions on senior Turkish officials, which led to retaliatory measures by Ankara, according to AFP.

On Wednesday, a Turkish delegation met both officials of the State and Treasury Departments to resolve some of the disputes. However, there was no sign of a breakthrough, Reuters reported.

The announcement led to the Turkish lira plunging more than 20% against the dollar, reported The Guardian. Investors in Turkey are opting to buy the dollar, yen, and other safe assets in a financially volatile market. Over the last year, the lira has dropped by almost 50% against the dollar.

Meanwhile, Turkish President Recep Tayyip Erdogan called on citizens to support the struggling lira, exhorting them to exchange their dollars and gold for the national currency, reported AFP. “We will not lose the economic war,” state-run TRT Haber television quoted Erdogan as saying. “If you have dollars, euros or gold under your pillow, go to banks to exchange them for Turkish lira. It is a national fight.”