Antony Jenkins, chief executive at Barclays, apologised for the bank's role in the scandal.
The misconduct at the core of these investigations is wholly incompatible with Barclays' purpose and values and we deeply regret that it occurred.
I share the frustration of shareholders and colleagues that some individuals have once more brought our company and industry into disrepute.
RBS has also so far dismissed three staff and a further two are suspended.
The serious misconduct that lies at the heart of today's announcements has no place in the bank that I am building.
Pleading guilty for such wrongdoing is another stark reminder of how badly this bank lost its way and how important it is for us to regain trust.
Royal Bank of Scotland i among five banks hit with fines over involvement in the rigging of global currency markets and has agreed to pay $669 million (£430 million) to US authorities.
It comes on top of a £399 million penalty last November, including £217 million by the FCA and $290 million (£186 million) by the US Commodity Futures Trading Commission (CFTC).
RBS has reported a £446 million loss in Q1 after restructuring and currency-manipulation probes, the state-backed lender has revealed today.
The bank, which is 80% owned by the taxpayer, was hit by restructuring costs of £453 million and £856 million in "litigation and conduct" charges.
Adjusted operating profit, excluding one-off charges, was up 16% to £1.63 billion as the bank benefited from "generally benign credit conditions".
The Royal Bank of Scotland was fined for "very serious" failings that left customers unable to access "basic banking services", said Tracey McDermott from the Financial Conduct Authority.
Business Secretary Vince Cable said the Royal Bank of Scotland's IT systems were "decades out of date" after the bank was fined £56 million for a computer failure that left customers unable to access their accounts.
This is another disastrous fine for RBS after a series of failures. RBS's priorities under Fred Goodwin meant that it neglected its IT systems, which in some cases are now decades out of date.
The new management is taking action by compensating people and investing in new IT which is right, but in many cases it's too little too late.
What matters now is that RBS can continue to overhaul its digital infrastructure to provide the modern services customers and businesses rightly expect.
The Financial Conduct Authority said it fined the Royal Bank of Scotland for failing put in place resilient IT systems.
Tracey McDermott, director of enforcement and financial crime at the FCA, said:
Modern banking depends on effective, reliable and resilient IT systems. The banks' failures meant millions of customers were unable to carry out the banking transactions which keep businesses and people's everyday lives moving.
The problems arose due to failures at many levels within the RBS Group to identify and manage the risks which can flow from disruptive IT incidents and the result was that RBS customers were left exposed to these risks.
A computer systems failure at RBS, Natwest and Ulster Bank in 2012 affected 6.5 million customers - around 10 percent of the entire UK population.
10% of uk population was hit by the RBS/NatWest computer failure in 2012
The RBS group was today fined £56 million over the crash.
RBS chairman Philip Hampton has apologised to the bank's customers for the "unacceptable weakness" in its IT systems that left many unable to access their accounts.
Our IT failure in the summer of 2012 revealed unacceptable weaknesses in our systems and caused significant stress for many of our customers. I again want to apologise to all customers in the UK and Ireland that we let down.
I am confident that the progress we have made in increasing the resilience of our IT systems.