U.S. stock indices ended highly volatile Wednesday session mixed. An increase in crude prices drove oil-related stocks higher. The Dow industrials rose reversing an early loss of 120 points.

The Dow Jones Industrial Average gained 183.19 points, or 1.1%, to 16,336.66. The S&P 500 rose 9.5 points, or 0.5%, to 1,912.53 (its energy sector's 4% gain was the strongest). The Nasdaq Composite lost 12.71 points, or 0.3%, to 4,504.24.

Business activity in the U.S. services sector weakened in January, the Institute for Supply Management reported. The corresponding index declined to 53.5 from 55.8 in the previous month. Economists had expected the index to have declined only to 55.1.

Meanwhile Markit Economics released the final reading of January U.S. Services PMI on Wednesday. The final Services PMI declined to 53.2 from 54.3 in December compared to the preliminary reading of 53.7. This was the lowest level since the end of 2013.

This morning in Asia Hong Kong Hang Seng rose 1.38%, or 261.87, to 19,253.46. China Shanghai Composite Index rose 1.46%, or 39.94, to 2,779.19. The Nikkei declined 0.70%, or 119.94, to 17,071.31.

Asian stock indices outside Japan rose. However activity on Chinese stock markets is gradually decreasing ahead of the Lunar New Year holiday. Japanese stocks were weighed by a stronger yen, which is unfavorable for the country's exporters.