Stock index futures see-sawed on Tuesday as continued uncertainty over plans to stem the escalating debt crisis in Europe kept investors nervous.

German Chancellor Angela Merkel and President Nicolas Sarkozy were determined to do what is necessary and were going to take action today, a French government source said, but the French president's office denied a joint statement was planned.

Merkel sought to quash talk of an imminent Greek default, saying Europe was doing everything in its power to avoid a default.

European stocks rose slightly, helped by bank shares, after hitting new two-year lows on fears tied to the debt crisis. <.EU>

There are a lot of disagreements, arguments and no clear direction. The response so far (from the policymakers) has been reactive than proactive. They need to give a larger solution, not just a patchwork solution, and we haven't seen this yet, said Tim Ghriskey, chief investment officer of Solaris Asset Management in Bedford Hills, New York.

Contagion not only in the euro zone, but how that reflects on the U.S. debt is our main concern here.

S&P 500 futures fell 2.3 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures were off 6 points, but Nasdaq 100 futures rose 4.25 points.

Wall Street ended higher Monday, bouncing back after reports that Italy's finance minister met with a delegation of Chinese officials to discuss buying Italian bonds. But another report later indicated Beijing may not buy the debt due to unstable European bond markets.

In economic data, U.S. import prices fell in August due to lower fuel, food and industrial material costs, the Labor Department said Futures barely budged after the report.

At 2 p.m. EDT, the Treasury Department issues monthly budget data for August. Economists forecast a $132.0 billion deficit rising from $129.4 billion in July.

Best Buy Co Inc, the world's largest consumer electronics chain, backed its sales outlook for the year despite missing revenue expectations in the second quarter on weak demand for televisions. Its shares rose 0.8 percent to $25.15 in premarket trade.

Hewlett-Packard Co shares will be in the spotlight after it extended the deadline for its $11.2 billion takeover offer for British software company Autonomy Corp Plc . The offer gained acceptances from only 41.6 percent of shareholders.

Conglomerate General Electric Co hopes to double its business in Germany in five years, a GE executive told the Wall Street Journal.

Redbook releases its retail sales index of department and chain store sales for September versus August at 8:55 a.m. EDT. In the prior period, sales rose 0.4 percent.

Blackstone Group LP's former top Asia dealmaker is leaving the firm and returning to New York, sources said.

(Reporting by Angela Moon; Editing by Jeffrey Benkoe)