Wall Street opens higher after sell-off, Europe eyed

Dow Jones, S&P 500 index and Nasdaq up 0.5% each

U.S. stocks rose at the open on Tuesday, but caution prevailed as a Spanish bill auction met with falling demand and investors kept their focus on the euro zone debt crisis ahead of a summit later in the week.

The Dow Jones industrial average was up 25.66 points, or 0.21 percent, at 12,528.32. The Standard & Poor's 500 Index  was up 3.08 points, or 0.23 percent, at 1,316.80. The Nasdaq Composite Index was up 9.13 points, or 0.32 percent, at 2,845.29.