Benchmark indices Sensex and Nifty inched higher in opening trade on Friday amid buying in bank stocks and a rally in the US markets, but later turned flat as investors stayed on the sidelines ahead of India's upcoming trade deal with the US.

The 30-share BSE Sensex went up by 67.34 points to 83,306.81 in opening trade. The 50-share NSE Nifty inched higher by 23.55 points to 25,428.85.

Later, both the key indices faced volatile trends and were trading flat. The BSE benchmark quoted 13.55 points down at 83,221.65, and the Nifty traded 4.15 points lower at 25,400.40.