Later, both the benchmark indices gave up all the early gains and were trading lower. The Sensex traded 214.84 points lower at 66,687.07 while the Nifty fell 55.80 points to 20,040.80.
Among the Sensex firms, UltraTech Cement, Mahindra & Mahindra, Axis Bank, Wipro, Hindustan Unilever, Sun Pharma, Kotak Mahindra Bank and Larsen & Toubro were the major gainers.
Tata Steel, Reliance Industries, Tata Motors and NTPC were among the laggards.
In Asian markets, Shanghai and Hong Kong traded with gains, while Seoul and Tokyo quoted in the negative territory.
The US markets ended mostly lower on Wednesday.
Overnight weakness in the US markets and subsequent fall in Asian indices could limit the gains, Prashanth Tapse, Senior VP (Research), Mehta Equities Ltd, said in his pre-opening market comment.
"As traders square off their positions on the monthly expiry day today, intra-day volatility could be seen," he added.
Global oil benchmark Brent crude declined 0.18 per cent to USD 82.95 a barrel.
Foreign Institutional Investors (FIIs) bought equities worth Rs 71.91 crore on Wednesday, according to exchange data.
The BSE benchmark jumped 727.71 points or 1.10 per cent to settle at 66,901.91 on Wednesday. The Nifty climbed 206.90 points or 1.04 per cent to reclaim the 20,000-mark after a gap of over two months. It ended at 20,096.60.