LONDON — Robert E. Diamond Jr., the former chief executive of Barclays who resigned because of a scandal involving interest rate manipulation, defended his testimony to a British parliamentary committee as lawmakers called more senior officials to appear.

Late Tuesday, Diamond responded to criticism from British politicians that he had not been completely forthcoming last week at a hearing on the Barclays case.

“Any such suggestion would be totally unfair and unfounded,’’ Diamond wrote in a letter to Andrew Tyrie, the committee’s chairman. ‘‘The comments made at today’s hearing have had a terribly unfair impact upon my reputation.’’

Diamond said he would be willing to discuss the issue with British lawmakers. A number of committee members have called for him to give more testimony.

However, there may not be time. The committee has one week before it recesses for the summer, and other officials have already been slated to give testimony Monday.

‘UNFOUNDED’

That list includes top executives from the Financial Services Authority, including the regulator’s chairman, Adair Turner; Andrew Bailey, the head of the prudential business unit; and Tracey McDermott, the acting head of the enforcement and financial crime division. Jerry del Missier, a senior Barclays official who resigned last week, is also set to appear.

The committee is investigating the manipulation of the London interbank offered rate, or Libor. The rate underpins trillions of dollars of financial products, including mortgages, student loans, and complex derivatives.

In late June, Barclays agreed to pay $450 million to British and US authorities to settle claims that it submitted bogus rates to deflect concerns about its health and improve profits.

Politicians in Washington and London are questioning whether officials did enough to avoid the scandal.

The New York Fed said Tuesday that it had received ‘‘occasional anecdotal reports from Barclays of problems with Libor’’ as far back as late 2007. Barclays has said that it had informed US and British regulators about concerns with the rate, but officials did not address the problems.

On Tuesday, members of the parliamentary committee focused their anger on Marcus Agius, Barclays’ chairman, asking him about the actions of Diamond and the culture inside the bank. Questions centered on two letters to Barclays from British regulators who asked questions about Diamond’s management style.

During his testimony last week, Diamond said the bank had maintained a good relationship with the authority, adding that he did not recall that the regulator had questioned the bank’s activities or its internal culture.

On Tuesday, panel members asked Agius about Diamond’s testimony. “Would you say that Mr. Diamond lied to this committee?” David Ruffley, a member of Parliament, asked Agius.

“I can’t comment on Mr. Diamond’s testimony,” Agius said.