The BSE benchmark Sensex today fell by over 112 points to close at one-week low of 20,111.61, mainly due to profit booking in interest rate sensitive stocks, including realty, auto and banking.

The 30-share index lost 112.37 points, or 0.56 per cent, to close at 20,111.61. It had lost 62 points yesterday.

Similarly, the broad-based National Stock Exchange index, Nifty, declined by 42.80 points, or 0.70 per cent, to 6,114.10.

Also, the MCX-SX flagship index SX40 closed lower by 66.13 points, or 0.55 per cent, at 11,881.37.

Brokers said Sensex climbing over a two-year high last week advised investors to book profits.

They said the market sentiment was further dampened on weak global trend ahead of the US Federal Reserve's meeting.

Investor confidence also shaken as brokerage firm Barclays Capital lowering India's growth forecast to 6 per cent for 2013-14, from earlier projection of 6.2 per cent, citing "recent disappointments" in economic activity.

Of the 30 shares, 21 stocks declined led by NTPC, Tata Motors.

The country's largest car-maker Maruti Suzuki dropped by 2.49 per cent to Rs 1,698.45 on reports Life Insurance Corporation of India has sold 2.53 per cent stake in the company over a period of almost six months.

In sector-wise performance, the realty sector suffered the most by losing 2.59 per cent to 1,965.71 followed by auto index by 1.75 per cent to 11,096.87. Power index fell by 1.06 per cent to 1,815.40 and banking index by 0.88 per cent to 14,941.46.