Gary Cohn exit adds to Wall Street trade war fears; Dow drops 1%

Worries over the threat to global trade that U.S. moves would represent have dominated Wall Street trading for almost a week.

Wall Street's main indexes fell on Wednesday as investors worried the exit of staunch free trade supporter Gary Cohn from the White House made the imposition of hefty steel and aluminium tariffs and eruption of a global trade war more likely.

The Dow fell as much as 1 percent at opening before trimming some of those losses as markets again debated how serious Donald Trump was about a protectionist shift that economists say could damage growth worldwide.

Playing in to that recovery was a Bloomberg interview in which White House trade adviser Peter Navarro, who favours strong tariffs, said he