MUMBAI: The benchmark BSE Sensex plunged over 521 points and the NSE Nifty fell below 7,700-mark in early trade today as retail investors booked profits after amid sustained capital outflows by foreign funds.

A weak trend on other Asian markets as investors turned cautious ahead of the U.S. job data to be released later in the day, also triggered selling by participants.

The 30-share barometer, which gained 311.22 points in the previous session, tanked 521.63 points, or 2.02 percent, to 25,243.15. All the sectoral indices, led by realty and bankex, were trading in the negative zone with losses of up to 3.75 percent.

The National Stock Exchange index Nifty dipped below the crucial 7,700-mark by falling 134.10 points, or 1.71 percent, to 7,688.90.

Brokers said besides profit-booking by speculators and sustained capital outflows by foreign funds, a weak trend on other Asian bourses with investors awaiting a key U.S. jobs report influenced sentiments here.

The European Central Bank indicating that it could expand its stimulus also weighed on the market sentiment, they said.

Brokers also said that fears of poor agriculture output as monsoon deficit widened triggered selling in stocks.

Among other Asian markets, Japan's Nikkei was trading 1.13 percent down, while Hong Kong's Hang Seng shed 0.19 percent in early trade today.

The U.S. Dow Jones Industrial Average, however, ended 0.14 percent higher in yesterday's trade.