U.S. stocks open higher as European equities rebound

U.S. stocks opened mildly higher Wednesday as the rebound in European stock markets soothed anxious investors.

European shares bounced back Wednesday from the previous day's plunge, as European Central Bank (ECB) President Mario Draghi said the ECB will adjust the size of monetary stimulus, composition and duration if more monetary policy impulse should become necessary.

On Tuesday, European shares ended drastically lower, with Germany's benchmark DAX index at the Frankfurt Stock Exchange diving 3.8 percent, as a result of Volkswagen's emissions scandal.

The German carmaker's shares plummeted 19.8 percent on Tuesday, following a deep decline of 18.6 percent on Monday.

Meanwhile, some analysts believed that uncertainty about the timing of interest rate hikes by the U.S. Federal Reserve had led to increased volatility.

The U.S. central bank held its benchmark rate near zero after concluding its two-day monetary policy meeting Thursday. Most Fed officials, however, still expect a rate increase this year, the first in nine years.

Shortly after the opening bell, the Dow Jones Industrial Average added 14.22 points, or 0.09 percent, to 16,344.69. The S&P 500 gained 2.02 points, or 0.10 percent, to 1,944.76. The Nasdaq Composite Index was up 9.73 points, or 0.20 percent, to 4,766.46.

On Tuesday, U.S. stocks suffered big losses as the rout in European equity markets rattled nervous investors. Endi