An extreme, protracted trade war between the U.S. and China brings profound risks that could plunge millions of people into poverty, economists say.

The ripple effects of Donald Trump's global trade war are increasingly being felt across numerous industries all at once and on Wednesday were once again exerting pressure on U.S. stock markets that have been roiled for weeks by his erratic trade policies.

China tells domestic airlines not to place new orders for Boeing jets, adding new pressure to the struggling American plane maker.