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.

Trump has recently focused more on China, the world’s second-largest economy, which upped its own rhetoric against the world’s largest economy. China on Monday warned other countries against making trade deals with the United States “at the expense of China’s interest” as Japan, South Korea and others try to negotiate agreements.