NEW YORK, Jan. 17 (Xinhua) -- U.S. stocks finished mixed on Tuesday, dragged by losses in materials and communication services sectors.

The Dow Jones Industrial Average fell 391.76 points, or 1.14 percent, to 33,910.85. The S&P 500 sank 8.12 points, or 0.20 percent, to 3,990.97. The Nasdaq Composite Index increased 15.96 points, or 0.14 percent, to 11,095.11.

Six of the 11 primary S&P 500 sectors ended in red, with materials and communication services down 1.07 percent and 0.92 percent, respectively, leading the laggards. Technology rose 0.44 percent, the best-performing group.

U.S. markets were closed on Monday in observance of Martin Luther King Jr. Day.

For the week ending Friday, the Dow rose 2 percent, the S&P 500 advanced 2.7 percent and the Nasdaq gained 4.8 percent.