Futures on major U.S. stock indices point to lower opening on Tuesday as a fresh exchange of fire between North Korea and South Korea, and concerns over European debt crisis weighed on the sentiment.

Futures on the S&P 500 are down 0.77 percent, futures on the Dow Jones Industrial Average are down 0.61 percent and Nasdaq100 futures are down 0.57 percent.

North Korea shelled a South Korean island, triggering worries that the lingering tensions between the countries could worsen. Tensions are escalating in the region as fighter jets have been deployed on the South Korean side of the border for retaliatory action.

Investors believe that the bailout of Irish banks will not be enough to ensure the region's financial stability. Another concern is that austerity measures, attached as a condition of receiving bailout money, are difficult to implement politically and puts Ireland economic recoveries at risk.

Additionally, rating agency Moody's said Ireland's credit outlook worsened because the bailout shifts the burden of their banks' liabilities onto the government's balance sheet, even if the EU/IMF will help pay for some of that burden.

On the economic front, investors are eagerly waiting for the GDP numbers as well as existing home sales data to understand the current situation in the world’s largest economy.

Economists forecast the U.S. GDP growth in the third quarter to be revised up to 2.4 percent annualized rate from the 2 percent rate projected last month. In the second quarter, the economy grew at a 1.7 percent annual rate.

The National Association of Realtors (NAR) is due to report the sales of previously occupied homes after markets open. Economists are forecasting that existing home sales in October may ease to 4.42 million against 4.53 million in September.

On Monday, US stocks finished mixed, but bounced back from early lows on worries that Ireland’s debt crisis could spread to other peripheral euro zone nations, following a request by the Irish government for a multi-billion euro bailout.

The euro declined 0.57 percent to 1.3550 against the dollar on debt concerns and the yen gained 0.12 percent against the greenback.

Crude oil futures declined 0.50 percent to $81.33/barrel and gold futures advanced 0.24 percent.

European stock markets are currently trading lower with FTSE 100 down by 34.90 points, DAX30 down by 10.46 points and CAC 40 down by 32.80 points.