NEW YORK, Aug. 13 (Xinhua) -- U.S. stocks turned negative on Monday as investors were concerned that Turkey's financial crisis would affect the global economy.

At midday, the Dow Jones Industrial Average dropped 104.90 points, or 0.41 percent, to 25,208.24. The S&P 500 was down 6.96 points, or 0.25 percent, to 2,826.32. The Nasdaq Composite Index declined 4.21 points, or 0.05 percent, to 7,834.90.

All three major indices erased early gains as concerns over the Turkish financial crisis and possible regional and global contagion geopolitical tensions continued to weigh on the market sentiment.

Lennar Corp. and Goldman Sachs Group were among the worst performers. Shares of the companies slid 4.97 percent and 1.16 percent, respectively, around midday. Meanwhile, Twitter and Amazon were among the best performers, with their shares surging about 3 percent and 1 percent, respectively.

The Turkish lira plunged 20 percent against the U.S. dollar after U.S. President Donald Trump on Friday authorized the doubling of tariffs on steel and aluminum products from Turkey. Enditem