Traders work on the floor of the New York Stock Exchange
Traders work on the floor of the New York Stock Exchange, February 22, 2011. REUTERS

US stock slipped on the continued unrest in the Middle East and escalating tensions in Yemen.

The Dow Jones Industrial Average declined 21.39 points, or 0.18 percent, to trade at 12,015.14 at 3:02 p.m. EST. The S&P 500 Index dropped 4.12 points, or 0.32 percent, to trade at 1,294.26. The Nasdaq Composite fell 0.32 percent.

Crude oil futures surged almost 2 percent to trade at $104.95 per barrel.

In Libya, a civil war rages on between pro- and anti- Gaddafi forces with Western powers supporting the anti-Gaddafi forces through air strikes.

In Yemen, the situation appears unstable as top generals have defected and protestors continue to clamor for the immediate resignation of President Ali Abdullah Saleh.

The concern is that the unrest and instability there would spread to Saudi Arabia, the world's largest oil exporter. For the US, a particular fear is the resurgence of al-Qaeda in Yemen.

The situation at Japan’s nuclear power plants seem contained at this point. However, the positive development on this front has largely been discounted by the global markets rally on Monday.