NEW YORK — U.S. stocks are opening sharply lower, following a slump in global markets.

European markets were sliding Tuesday, led by a plunge in Greece on concerns that a political crisis there might jeopardize the country's finances.

Stocks also sank in China, snapping a months-long boom, after regulators there tightened rules for lending.

The Dow Jones industrial average dropped 164 points, or 0.9 percent, to 17,690 as of 9:45 a.m. Eastern time.

The Standard & Poor's 500 index fell 19 points, or 0.9 percent, to 2,041. The Nasdaq composite lost 49 points, or 1 percent, to 4,692.

The price of crude oil fell 50 cents to $62.56 a barrel in New York.

Government bond prices rose. The yield on the 10-year Treasury note slipped to 2.20 percent.