Stocks fell further in early afternoon trading on Monday, with the Nasdaq declining more than 2 percent and the Dow and S&P 500 down more than 1 percent each.

A downgrade of the semiconductor sector weighed on the tech sector, along with a weaker-than-expected sales forecast by communications equipment maker Ciena Corp .

The Dow Jones industrial average <.DJI> was down 106.00 points, or 0.87 percent, at 12,063.88. The Standard & Poor's 500 Index <.SPX> was down 14.66 points, or 1.11 percent, at 1,306.49. The Nasdaq Composite Index <.IXIC> was down 54.09 points, or 1.94 percent, at 2,730.58.

(Reporting by Caroline Valetkevitch; Editing by James Dalgleish)