Turkish President Recep Tayyip Erdogan on Saturday branded interest rates a "tool of exploitation" which should be kept as low as possible. "Interest rates should be kept to a minumum because they are a tool of exploitation that makes the poor poorer and the rich richer," Erdogan said in a speech in the Black Sea city of Rize. The nominally independent central bank has defied pressure over the last few weeks to hike interest rates in the face of high inflation and a collapsing currency. The lira tumbled 16 percent against the dollar on Friday. US President Donald Trump said Friday he had doubled tariffs on steel and aluminium from Turkey, adding to pressure on its troubled economy amid a diplomatic row with Washington over the detention of a pastor. "Those who challenge a country like Turkey for the sake of petty calculations will pay a price both in our region and in their own politics," the Turkish leader said. "We are never accepting this order which declared economic war to the entire world and which held countries to ransom through sanction threats," he added, referring to the US administration. Erdogan said high foreign exchange rates were the means used in plots against Turkey. "We know very well that the issue is not dollar, euro or gold. They are bullets, cannonballs and missiles of an economic war waged against our country," he said. He said his government had taken measures in response, and would continue to do so. President Recep Tayyip Erdogan (pictured July 2018) says that interest rates are "a tool of exploitation that makes the poor poorer and the rich richer"