NEW YORK (Reuters) - Stocks fell on Monday for the second straight session and the third in the last four trading days, led lower by basic materials shares after  China  trimmed its  growth target  for 2012.

The S& P 500 index opened lower and data showing the U.S. services sector expanded in February at its fastest pace in a year did little to stem the decline.

  China, the world's second-largest economy, lowered its 2012 growth target to an eight-year low of 7.5 percent and made expanding consumer demand its top priority, as Beijing looks to shrink the economy's reliance on external spending and foreign capital.

" That spooked everybody this morning. It started over in Asia, flowed right to Europe and flowed right over here," said Ken Polcari, managing director at ICAP Equities in  New York.

" The fact is they are guiding a little bit lower to control their inflation. It is not necessarily the end of the world, but it gave people a reason to take some money off the table."

Opponents of President Mahmoud Ahmadinejad were leading in Iran’s parliamentary election, which may strengthen the position of Supreme Leader Ayatollah Ali Khamenei.

Stocks (MXWD) fell for a second day after China announced the lowest economic growth target since 2004 and European services and manufacturing output was less than earlier estimated. The yen strengthened, while oil erased early declines amid concern about tensions with Iran.

Stocks declined Monday as concerns over Europe and China overshadowed a handful of better-than-expected economic news in the U.S.

Banks press Fed to limit information release: WSJ