Trump’s headbutting with Fed Chairman Jerome Powell should be “taken very seriously and very negatively,” said one strategist, as Trump slammed the central banker as a “major loser.”

U.S. indexes were on track to open lower on Monday after President Donald Trump's renewed attacks on Federal Reserve Chair Jerome Powell sparked concerns about the central bank's independence and rattled investors grappling with an escalating trade war.

U.S. stocks are falling as investors worldwide pull away from the U.S. because of uncertainty caused by President Donald Trump’s trade war.