Stocks: 'Early gains may be vulnerable'

NEW YORK (CNNMoney) -- U.S. stock futures were slightly higher ahead of the opening bell Tuesday, as investors awaited economic reports on housing and consumer confidence.

Dow Jones industrial average (INDU), S&P 500 (SPX) and Nasdaq (COMP) futures were up about 0.3% ahead of the opening bell. Futures measure current index values against perceived future performance.

Theres's still a lot of uncertainty in the market, between spreading urest in Libya and the Middle East, as well as Japan's recovery efforts and nuclear issues.

Stocks have been struggling to get out of their rut and "early gains might be vulnerable," said Marc Chandler, analyst for Brown Brothers Harriman.

U.S. stocks finished slightly lower Monday, snapping a three-day winning streak, after drifting into the red during the final hour of trading.

Monday night, President Barack Obama rejected criticism of his decision to commit U.S. forces to the U.N.-authorized military mission in Libya, saying there were strategic and moral reasons to act against Moammar Gadhafi.

In Japan, workers at the crippled Fukushima Daiichi nuclear plant struggled to keep reactors cool and prevent radioactive water from leaking into the ocean.

Meanwhile, investors are looking to the end of the week, when the government will release its key snapshot of the nation's job market.

Friday's monthly hiring and unemployment report from the Labor Department is expected to show the economy added 185,000 jobs in March, while the unemployment rate remained steady at 8.9%, according to economists surveyed by Briefing.com.

Economy: On tap before the start of trade is the S&P Case-Shiller home price index of 20 major cities for January. Home prices are expected to be down 3.3% in the month, according to economists surveyed by Briefing.com.

After the start of trade, the Conference Board will release March consumer confidence figures. Turbulence in the oil markets and concern over the Japanese nuclear crisis are expected to have dented sentiment considerably. Economists are looking for consumer confidence to fall to a reading of 65, down from 70.4 in February.

Companies: Shares of BP (BP) fell 2.5% in premarket trading after analysts at Collins Stewart reportedly downgraded the stock on concerns about its joint-venture with Russian oil and gas company Rosneft.

BP was also under pressure following a report that federal prosecutors are considering whether to pursue manslaughter charges against company managers for decisions made before the Deepwater Horizon oil rig exploded and killed 11 workers last year.

Apollo Group (APOL) was under pressure, with shares falling nearly 8% in premarket trading after the education provider lowered its outlook.

Shares of Lennar Corp (LEN) rose nearly 3%, after the homebuilder swung to a profit in the first quarter.

News Corp (NWS, Fortune 500) was also in focus amid speculation that the publishing company is in talks to hand over control of Myspace to Vevo.com, the online music website.

World markets: European stocks fell in morning trading. Britain's FTSE 100 edged lower 0.2%, the DAX in Germany sank 0.7% and France's CAC 40 tumbled 0.5%.

Asian markets ended the session lower. The Shanghai Composite fell 0.9% and Japan's Nikkei slid 0.2%, while the Hang Seng in Hong Kong ended little changed.

Currencies and commodities: The dollar fell against the euro and the British pound, but was steady versus the Japanese yen.

Oil for May delivery slipped 62 cents to $103.36 a barrel.

Gold futures for April delivery fell $6.50 to $1,413.40 an ounce.

Bonds: The price on the benchmark 10-year U.S. Treasury edged lower, with the yield rising to 3.46%.