Hillary Clinton said on Monday she does not need to apologize for using a private email account and server while she was secretary of state, because “what I did was allowed”.

In an interview with the Associated Press during a Labor Day campaign swing through Iowa, the frontrunner for the Democratic presidential nomination also said the lingering questions about her email practices have not damaged her campaign.

“Not at all. It’s a distraction, certainly,” Clinton said. “But it hasn’t in any way affected the plan for our campaign, the efforts we’re making to organize here in Iowa and elsewhere in the country. And I still feel very confident about the organization and the message that my campaign is putting out.”

Yet even in calling the inquiry into how she used email as the nation’s top diplomat a distraction, Clinton played down how it has affected her personally as a candidate.

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“As the person who has been at the center of it, not very much,” Clinton said. “I have worked really hard this summer, sticking to my gameplan about how I wanted to sort of reintroduce myself to the American people.”

Part of that includes, Clinton said, answering any questions about her email “in as many different settings as I can”. The one-on-one interview with AP was the second for Clinton in the past four days, after she told NBC News on Friday her decision not to use separate email accounts for her personal and public business wasn’t the “best choice”.

Clinton did not apologize for her decision when asked directly by NBC, “Are you sorry?”

Asked on Monday by the AP why she will not directly apologize, Clinton said: “What I did was allowed. It was allowed by the State Department. The State Department has confirmed that.

“I did not send or receive any information marked classified,” she said. “I take the responsibilities of handling classified materials very seriously and did so.”

Last year, Clinton turned over to the State Department roughly 55,000 pages of emails that she sent and received using a “home-brew” email server set up at her home in suburban New York, while serving as secretary of state from 2009 to 2013.

Clinton has said she set up her own system instead of using a State Department account for the convenience of using a single hand-held email device.

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The State Department is reviewing and publicly releasing those emails, some showing that Clinton received messages that were later determined to contain classified information, including some that contained material regarding the production and dissemination of US intelligence.

“There is always a debate among different agencies about what something should be retroactively [marked classified],” Clinton told the AP on Monday. “But at the time, there were none. So I’m going to keep answering the questions and providing the facts so that people can understand better what happened.”

Last month, Clinton gave the server to the FBI, along with a thumb drive kept by her attorney that contained copies of the emails.

“It is not a criminal investigation, it is a security review,” Clinton said. “People are asked to provide any copies of any of these materials that are the subject of the debate. So, I immediately said, ‘Turn over everything.’”

Clinton added: “I don’t know anything technical about servers. But I am informed it doesn’t have anything on it. But for safekeeping, turn it over as part of the security review.”