US stocks dived to session lows at midday Friday after Britain's surprise vote to leave the European Union, with both the Dow and S&P 500 down about three percent.

Near 1650 GMT, the Dow Jones Industrial Average was at 17,473.41, down 3.0 percent.

The broad-based S&P 500 shed 3.2 percent at 2,046.78, while the tech-rich Nasdaq Composite Index tumbled 3.7 percent to 4,728.22.