U.S. stocks closed mixed on Monday as investors focused on the Federal Reserve's annual meeting later this week.

With no major economic reports due out on Monday, investors focused on the Fed's upcoming annual symposium in Jackson Hole later this week. Ben Bernanke, the Fed's Chairman, will deliver a speech at the meeting.

The Fed's latest minutes of monetary policy meeting indicated that the central bank's willingness to introduce additional monetary easing policies went higher as weak economic growth worried the central bank.

Also raising the expectations, Charles Evans, the President of Chicago Federal Reserve Bank, said the central bank should "take actions now," buying bonds for as long as it takes to produce a steady decline in the employment rate.

However, Stephen Guilfoyle, U.S. economist of Meridian Equity Partners, told Xinhua that if the gross domestic product in the second quarter came closer to 2 percent on Wednesday, the hoping for more easing measures will fade.

"It may be good for the President, but it won't be good for those hoping for easing maneuvers to be made by the FOMC." said Guilfoyle.

Meanwhile, the European Central Bank's likely move also caught investors' attentions. The ECB said it may step into European country's bond markets to help push down the borrowing costs. Mario Draghi, president of the ECB, will also give a speech later this week at Fed's annual meeting.

The uncertainties of central banks' monetary policies added investors' concerns and weighed on the market. When the market closed, the Dow Jones industrial average slipped 33.30 points, or 0.25 percent, to 13,124.67. The Standard & Poor's 500 edged down 0. 69 points, or 0.05 percent, to 1,410.44. The Nasdaq Composite Index added 3.40 points, or 0.11 percent, to 3,073.19.

On corporate news, Apple won a 1.05 billion patent lawsuit against Samsung, which boosted its share price hitting an all-time high of 680.87 dollar a share in Monday's mid-day trading session.

Tiffany gained more than 7 percent on Monday despite the jeweler lowered its fiscal year earnings and revenue guidance for the second quarter.

On other market, the dollar gained against major currencies as risk-aversion appetite rose in market. Oil price plunged as Tropical storm Isaac compelled energy companies shutting down refiners.