U.S. stock index futures pointed to a lower open on Wall Street on Tuesday, with futures for the S&P 500 down 0.5 percent, Dow Jones futures down 0.5 percent and Nasdaq 100 futures down 0.6 percent.

Alcoa Inc will be the main focus after posting a narrower quarterly loss that fell short of expectations after the bell on Monday.

The company blamed higher power bills, a weak dollar and costs of temporarily shutting smelters in Italy, and said while aluminum prices were climbing, demand from some customers, especially planemakers and the commercial construction sector, was not expected to improve soon.

Frankfurt-listed shares in Alcoa were down 6.1 percent, while shares in rival Aluminum Corp of China Ltd (Chalco) <2600.HK> dropped 2.4 percent in Hong Kong and European mining shares such as Rio Tinto and Xstrata were among the biggest losers in Europe where the FTSEurofirst 300 <.FTEU3> index was down 0.5 percent.

Chevron Corp shares fell 1.3 percent to $79.84 after the bell on Monday after the energy company provided an interim update on its fourth quarter.

Kraft Foods will also be in the spotlight after British confectioner Cadbury posted solid 2009 results and an upbeat outlook in its last move to rebuff Kraft's $17 billion hostile takeover bid.

Also weighing on overall sentiment, China's central bank signaled in its open market operations it was tightening monetary conditions at a faster than expected pace in response to increasing concerns about the economy overheating.

American Airlines and partners in the Oneworld alliance sweetened their offer to Japan Airlines <9205.T> to $1.4 billion to keep the struggling national carrier from joining hands with rival Delta Air Lines .

Revenue at Airbus parent EADS fell almost 4 percent to around 41.7 billion euros ($60.6 billion) in 2009, the European aerospace group said on Tuesday.

Mattel , the world's leading toymaker, said it had seen very strong sales for its Christmas hit Fashionista Barbie doll following a recent revamp of its 50-year-old mainstay product.

Prudential Financial Inc

is set to pick a buyer for its South Korean funds and brokerage units by February, in a deal estimated at up to $900 million that could pressure other struggling foreign financial firms to follow suit.

U.S. industrial shares lifted the Dow and the S&P 500 on Monday to new 15-month highs after China bolstered expectations the world economy would strengthen, but Nasdaq fell on profit-taking in tech stocks.

The Dow Jones industrial average <.DJI> gained 45.80 points, or 0.43 percent, to 10,663.99. The Standard & Poor's 500 Index <.SPX> rose 2.00 points, or 0.17 percent, to 1,146.98. The Nasdaq Composite Index <.IXIC> fell 4.76 points, or 0.21 percent, to 2,312.41.

(Reporting by Blaise Robinson; Editing by Dan Lalor)