NEW YORK - U.S. stocks closed mixed on Monday, amid weakness in the materials sector.

The Dow Jones Industrial Average decreased 126.15 points, or 0.36 percent, to 34,630.24. The S&P 500 was down 3.37 points, or 0.08 percent, to 4,226.52. The Nasdaq Composite Index increased 67.23 points, or 0.49 percent, to 13,881.72.

Seven of the 11 primary S&P 500 sectors ended in red, with materials down 1.23 percent, leading the laggards. Real estate rose 0.91 percent, the best-performing group.

U.S.-listed Chinese companies traded mostly lower with eight of the top 10 stocks by weight in the S&P U.S. Listed China 50 index ending the day on a downbeat note.

Last week, Wall Street's major averages eked out modest gains as investors cautiously assessed the picture of the economic recovery.

For the week ending Friday, the Dow and the S&P 500 rose 0.7 percent and 0.6 percent, respectively, while the tech-heavy Nasdaq climbed 0.5 percent.