U.S. President Donald Trump on Monday said U.S. tariffs on China bring billions of dollars into U.S. coffers. He said China's retaliatory tariffs can have no effect on the U.S. economy. The escalation of the U.S.-China trade war sent stock markets tumbling on Monday, with the Dow Jones Industrial Average falling more than 600 points. Earlier, China announced new tariffs of up to 25 percent on $60 billion worth of U.S. goods, starting June 1. VOA's Zlatica Hoke has more.