Stock indexes drop, extending losses to third week, as oil prices fall and dollar strengthens

Stocks are closing lower, led by declines in utilities and materials stocks.

The price of oil took another sharp turn lower Friday and the dollar moved higher against the euro, threatening to pinch the profits of big U.S. exporters.

The Dow Jones industrial average slumped 145 points, or 0.8 percent, to 17,749.

The Standard & Poor's 500 index fell 12 points, or 0.6 percent, to 2,053. The Nasdaq composite declined 21 points, or 0.4 percent, to 4,871.

Crude oil fell $2.21, nearly 5 percent, to $44.84 a barrel in New York. Oil has fallen 10 percent this week and is close to a six-year low.

Rig operator Transocean dropped 5 percent.

U.S. government bond prices didn't move much. The yield on the 10-year Treasury note was unchanged at 2.12 percent.