Barclays boss Bob Diamond admitted he was disappointed that the rate-rigging scandal happened on his watch and would "make sure that it cannot happen again".
The comments in a memo to staff came hours after Barclays chairman Marcus Agius resigned and announced an internal review into the bank's "flawed" practices.
Despite mounting calls for his own departure, Mr Diamond showed no signs of stepping down soon, telling employees in a lengthy letter: "I am committed to ensuring the recommendations of this review are implemented in full."
The memo emerged after the Serious Fraud Office said it hoped to decide within a month on whether a criminal prosecution in relation to the rate-fixing was appropriate. Barclays has been at the centre of a gathering storm over banking ethics after it was last week fined £290m by UK and US regulators for manipulating the Libor, the rate at which banks lend to each other.
In the letter, Mr Diamond, who will appear before the Treasury Select Committee tomorrow, said it had been "an incredibly tough period" for staff given the "nature and volume of negative comment" against Barclays.
He said: "I understand why the reaction has been severe. No one is more sorry, disappointed and angry about these events than I am."
He added: "I am disappointed because many of these behaviours happened on my watch. It is my responsibility to make sure that it cannot happen again."
He went on: "I am angry because the impression has been given that the behaviour revealed in the documents last week is indicative of the culture at Barclays generally. We all know that these events are not representative of our culture."
Turning to taking action against those involved, Mr Diamond said that an internal disciplinary process, which began some time ago, will be completed swiftly.
There have been mounting calls for criminal prosecutions to be brought against those responsible for fixing the Libor for their own personal benefit.
The Bank of England was also drawn into the affair after it emerged staff mistakenly thought they were instructed by the central bank to lie in their rate submissions. The Financial Services Authority's report said there had been a misunderstanding arising from a conversation between Bank Deputy Governor Paul Tucker, a favourite for the Governor role, and an unidentified senior Barclays manager on October 29 2008.
Nearly two-thirds of banking customers no longer trust their lender to look after their money, a poll has revealed.
As public outrage over the unfolding banking crisis grows, a YouGov poll commissioned by the Sunday Times showed 60% of people losing faith in their bank.
Some 49% believe the high-street banks to be dishonest while 45% think of them as incompetent, the poll revealed. And just 1% of respondents believe that senior executives of the biggest banks have improved their behavior since the financial crisis began.