U.S. stocks fell on Tuesday as investors turned cautious ahead of earnings season, and talk of a second stimulus package underscored worries about the U.S. economic recovery.

Signaling the economy's difficulty in rebounding from a deep recession, a member of the Obama administration's economic advisory panel said the United States should plan to possibly provide a second round of stimulus funds to prop up the economy.

Talk of a new stimulus plan is actually a confidence killer, said Joseph Battipaglia, market strategist at Stifel Nicolaus in Yardley, Pennsylvania. That would mean we've added a trillion dollars to debt without anything to show for it.

Investor concerns over mounting debt was also underpinned by a report showing cash-strapped consumers fell behind on their credit card bills in record numbers in the first quarter.

Investors also have their eyes set on the quarterly earnings season that gets underway this week, with Alcoa Inc set to report on Wednesday. Alcoa, a Dow component, is expected to post a third consecutive quarterly loss.

We're coming into earnings, which are expected to be down, and the anticipation is that Alcoa's report will be even worse than expected, Battipaglia added.

The expectation of a speedy recovery is starting to slow because there is no evidence to support it.

The Dow Jones industrial average <.DJI> shed 70.58 points, or 0.85 percent, to 8,254.29. The Standard & Poor's 500 Index <.SPX> fell 6.29 points, or 0.70 percent, to 892.43. The Nasdaq Composite Index <.IXIC> dropped 14.41 points, or 0.81 percent, to 1,772.99.

The loss of confidence in the economic recovery has sent oil prices tumbling. New York crude fell more than 1 percent, and its five-session slide has pressured energy stocks, a large sector of the S&P 500.

Oil services company Schlumberger Ltd fell 2.5 percent to $50.19 while blue-chip Exxon Mobil lost 1.8 percent to $66.84.

The S&P energy sector <.GSPE> index lost 1.7 percent.

The broad S&P 500 index rallied about 40 percent from 12-year lows hit in early March on expectations of a speedy economic recovery. But the rally wilted in the last month, as investors sought stronger evidence that conditions were improving.

(Editing by Padraic Cassidy)