Stock index futures rose on Tuesday a day after a week-long rally was halted as investors waited to see if the Federal Reserve's policy-setting panel offers aid to a sputtering U.S. economy.

At the two-day meeting that starts Tuesday, the Fed is expected to try to push already low long-term interest rates even lower by tilting toward longer-duration bonds in its portfolio, a move known as Operation Twist.

Equity futures shrugged off Standard & Poor's downgrade of Italy's credit rating by one notch, an unexpected move that increased strains on the debt-stressed euro zone.

After the initial downward response in the S&P futures to the S&P downgrade of Italy, markets realized again that rating agencies follow the markets, never lead them, said Peter Boockvar, said Peter Boockvar, equity strategist at Miller Tabak & Co in New York.

The FOMC 2-day meeting begins today, and as I've said repeatedly, incremental Fed action is now impotent and in fact damaging.

S&P 500 futures gained 10 points and were above 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 up 81 points, and Nasdaq 100 futures rose 22.25 points.

International lenders told Greece Monday it must shrink its public sector to avoid running out of money within weeks, worrying investors who dumped risky assets.

The U.S. Commerce Department releases housing starts and permits for August at 8:30 a.m. EDT. Economists forecast a 590,000 annualized rate for starts versus 604,000 in July, and 590,000 permits in August versus 601,000 in the prior month.

At 8:55 a.m. EDT, Redbook releases its retail sales index of department and chain store sales. In the prior period, sales rose 0.2 percent.

Samsung Electronics Co <005930.KS> is considering a lawsuit to ban sales of Apple Inc's new iPhone, sources told Reuters, in what could be its strongest step to defend against claims it copied Apple product designs.

Bank of China, a big market maker in China's onshore foreign exchange market, has stopped foreign exchange forwards and swaps trading with several European banks due to the unfolding debt crisis in Europe, sources told Reuters.

Securities regulators have subpoenaed hedge funds and other trading firms as they probe possible insider trading before the U.S. government's long-term credit rating was cut last month, the Wall Street Journal reported, citing sources.

U.S. reinsurer Transatlantic Holdings Inc , which rejected a takeover offer from Warren Buffett's Berkshire Hathaway Inc , is exploring a limited standstill agreement with Validus Holdings Ltd , the Wall Street Journal reported, citing sources.

U.S. President Barack Obama laid out a $3.6 trillion plan on Monday to cut budget deficits partly by raising taxes on the rich, but Republicans called it a political stunt and said the proposal had little chance of becoming law.

UBS AG's chief executive will seek a vote of confidence at a board meeting for plans to slash the investment banking division that caused a $2.3 billion loss due to unauthorized trading, a Swiss newspaper reported. U.S.-listed shares of UBS fell 1.2 percent to $11.37 in premarket trade.

European shares were higher Tuesday as investors went bargain hunting following sharp falls in the previous session.

U.S. stocks fell Monday but staged a late comeback after fears of a looming Greek debt default diminished on news of a possible deal to advance new bailout funds to Greece.

(Reporting by Angela Moon; editing by Jeffrey Benkoe)