Indian shares tumbled over 2 per cent on Monday, with investors dumping risky assets as oil prices soared after the United States and European allies were said to be mulling a Russian oil import ban.

The blue-chip NSE Nifty 50 index was down 2.39 per cent at 15,857 and the S&P BSE Sensex dropped 2.52 per cent to 52,963.78 in the initial hour of trading session. Both the indexes extended losses to a fourth straight session. Last week, they also posted their fourth consecutive weekly loss.

Oil prices surged on Monday after the US and European allies explored a Russian oil import ban, while delays in the potential return of Iranian crude to global markets sped up supply fears.

India is the world's third-largest importer of crude oil, and rising prices push up the country's trade and current account deficit while also hurting the rupee and fuelling imported inflation.

The Nifty's bank index, financial services index , private sector bank index, auto index and IT index were among the top losers, dropping between 2 per cent and 4 per cent