U.S. stock index futures rose on Tuesday as the U.S. dollar hit a 1-year low against the euro ahead of the start of a Federal Reserve monetary policy meeting, boosting oil and metals prices.

The Federal Reserve starts its two-day monetary policy meeting on Tuesday with a decision on interest rates due at around 2:15 p.m. (1815 GMT) the following day. Markets will be looking for any comment indicating how the Fed might wind down its financial stimulus measures, given the improving macroeconomic data.

The euro reached a one-year high against the U.S. dollar as dealers took advantage of the greenback's gains the previous session to resume selling ahead of the Fed meeting and a G20 summit later in the week. The dollar index <.DXY> tumbled 0.8 percent.

The dollar is under pressure this morning, and that is (increasing) risk appetite in commodities, said Peter Cardillo, chief market economist at Avalon Partners in New York.

He said the shift to commodities is spilling over into the equity markets as well.

Crude futures rose 1.5 percent to $70.77 per barrel and copper for three-month delivery rose 1.8 percent.

Citigroup Inc shares rose 2.5 percent to $4.54 before the opening bell. The Government of Singapore Investment Corp (GIC) said it has cut its stake in Citi through open market sales to below 5 percent. GIC held more than 9 percent of Citi on September 11, when it converted its preference shares to ordinary shares.

S&P 500 futures rose 7.5 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 gained 61 points and Nasdaq 100 futures added 10.25 points.

The day's economic agenda includes Redbook's Retail Sales Index of weekly department and chain store sales at 8:55 a.m.

At 10 a.m. (1400 GMT), a home prices index and a regional manufacturing survey will give investors further insight into the state of the U.S. economy.

Credit Suisse downgraded Dell Inc to neutral and recommended Hewlett-Packard Co , Apple Inc and EMC Corp . Dell shares fell 0.6 percent to $15.91 in premarket trading while Dow component HP rose 2 percent to $47.30. .

The head of Cadbury PLC , which is facing a possible takeover by U.S. food giant Kraft Foods Inc , said there were some complementary elements in the two companies' portfolios, according to a Wall Street Journal report. But Cadbury Chief Executive Todd Stitzer said his company's shareholders still reject the deal at the $16 billion price offered by Kraft.

Samsung Electronics <005930.KS>, the world's biggest maker of memory chips, said on Tuesday it remains cautious about the sector's outlook even as the industry emerges from its two-year slump.

The Dow industrials and the S&P 500 index fell on Monday as a drop in oil and other commodity prices hurt energy and materials stocks. But the Nasdaq rose, buoyed by a broker's upgrade in the biotechnology sector.

(Editing by Padraic Cassidy)