The dollar tumbled on Monday to its lowest level in three years as investor confidence in the U.S. economy took another hit over President Donald Trump's attacks on the Federal Reserve chairman, potentially putting the central bank's independence under threat.

The benchmark dollar index has fallen roughly 5 percent since early April, when Trump roiled markets with his sweeping tariffs.

A flight from U.S. financial assets prompted by President Trump’s trade war is subsiding as the White House appears increasingly keen to strike a new trade deal with top U.S. trading partner