The Reserve Bank of India (RBI) sold an estimated $2 billion to $3 billion on Thursday to defend the rupee against sustained pressure, and stepped in again on Friday, helping the currency strengthen past the 96-per-dollar mark, according to bankers cited by Reuters. The rupee rose 0.64 per cent to close at 96.20 against the US dollar on Thursday after the intervention and extended gains on Friday as the central bank resumed dollar sales. Bankers said the RBI intervened through large state-run banks even before markets opened on Thursday, with around $500 million reportedly sold in pre-market trading.