U.S. stock index futures were little changed on Wednesday, after modest losses in the previous session, as worry continued over debt issues in the euro zone, Japan's nuclear crisis and violence in the Middle East and North Africa.

Concerns over euro area debt levels will again be in focus as Portugal's parliament was expected to reject government austerity measures in a vote scheduled for 1500 GMT, with Prime Minister Jose Socrates threatening to resign if the opposition rejected the proposals.

Violence in parts of the oil-rich Middle East and North Africa, including Libya, Syria and Yemen, lifted Brent crude futures up 42 cents to $105.39 a barrel, reigniting concerns of inflation on a fragile U.S. economic recovery.

U.S.-listed Japanese stocks will be in focus as further disruptions to supply chains were seen hitting individual companies in the wake of Japan's massive earthquake, with Sony cutting output at five more plants and Toyota Motor saying it would keep assembly lines shut until at least Saturday.

Ford Motor Co , however, said on Wednesday it had saw no immediate impact or disruption from the earthquake.

Japan estimated direct damage from the earthquake and tsunami to be 16-25 trillion yen ($185-$308 billion), making it the world's costliest natural disaster.

U.S. new home sales data for February is due at 10:00 a.m. Economists in a Reuters survey expect new sales have likely risen to a 290,000 annual rate from January's 284,000.

S&P 500 futures fell 1 point and were in line with 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 fell 1 point, and Nasdaq 100 futures dropped 5.75 points.

General Motors Co sold its preferred shares in auto lender Ally Financial Inc for $1 billion to strengthen its balance sheet.

In Europe, the FTSEurofirst 300 <.FTEU3> index of top shares rose slightly.

Wall Street snapped a three-day winning streak on Tuesday, with trading volume the lowest of the year.

(Reporting by Angela Moon; Editing by Padraic Cassidy)