Mumbai: The Bombay Stock Exchange benchmark Sensex declined by over 200 points in opening trade on Friday as funds and retail investors locked in gains recorded in Thursday's rally.

The 30-share BSE index, which had gained 252.05 points in the previous session, fell by 202.56 points, or 1.21 percent, to 16,495.51 in the first five minutes of trade.

Stocks of Reliance Anil Dhirubhai Ambani Group firms RCom, Reliance Capital and Reliance Infra suffered sharp setbacks and were trading up to 7 percent lower in opening trade after the CBI informed the Supreme Court that it was still probing whether Chairman Anil Ambani had any role in the 2G scam.

In a similar fashion, the wide-based National Stock Exchange Nifty index declined by 55.45 points, or 1.11 percent, to 4,960.00.

All the sectoral indices, barring consumer durables, were trading in the negative zone, with losses of up to 1.44 percent.

Brokers said investors cashing in on gains registered in the previous session in the absence of any positive factors mainly dampened the trading sentiment.

In the Asian region, Hong Kong's Hang Seng index was down by 1.28 percent, while Japan's Nikkei index moved up by 0.25 percent in early trade on Friday. The US Dow Jones Industrial Average ended 1.30 percent higher in Thursday's session.