Royal Bank of Scotland has come under the radar of the US federal investigators for the bank’s alleged financial dealings with Iranian financial intuitions.

RBS’ relation with Iran is being investigated by the US Federal Reserve and Department of Justice, and if any evidence found against the UK lender, then it would inevitably invite financial penalty, as reported by the Financial Times.

The US authorities have already penalized HSBC, Barclays, Standard Chartered over their act of breaches of Iran sanctions.

Although, the bank voluntary informed the US and the UK authorities on the violation of trade sanction imposed on Iran, it is unlikely to get lesser treatment by the federal authorities.

Sources familiar with the matter were cited by the news agency as saying, the bank probed the matter in internal level and found a risk manager guilty and departed him from the bank.

The bank’s woes are compounding with the current investigation by the US, as it is already crippled by series of scandals including an IT failure mis-selling of retail and small-business products and most recently, the Libor rate rigging scandal.

Commenting on the series of regulatory events, RBS said in its half yearly report, "The investigation costs, remediation required or liability incurred could have a material adverse effect on the group’s net assets, operating results or cash flows in any particular period."