The Democratic candidate for vice-president, Tim Kaine, on Sunday defended Hillary Clinton against criticism over her handling of classified information while secretary of state, saying she was unaware of the sensitivity of some information she exchanged over email because it had been “improperly labeled”.



Donald Trump’s running mate, Indiana governor Mike Pence, led the charge for the Republicans, telling NBC’s Meet the Press the release of FBI interview records on Friday was “just more evidence that Hillary Clinton is the most dishonest candidate for president of the United States since Richard Nixon”.

In July, the FBI rebuked Clinton for her use of a private email server during her tenure as secretary of state from 2009 to 2013, saying she was “extremely careless” in her handling of classified information. The agency recommended however that no criminal charges be filed.

According to records released by the FBI on Friday, Clinton told FBI investigators in a July interview she could not recall getting any briefings on how to handle classified information or comply with laws governing the preservation of federal records.

Kaine, a senator from Virginia who sits on the Senate foreign relations and armed services committees, told ABC’s This Week that the volume of information received by government officials often makes it difficult to know what information has been declared classified.

“There were emails that contained classified information that had been improperly marked,” he said. “So when she received the email, the material that was classified – which is supposed to be flagged and identified as classified – in many instances was improperly labeled.

“We look at so much material, unless it is specifically pulled out and identified, it is difficult to know sometimes whether a statement or a paragraph is classified or not.”

On NBC, after comparing Clinton and Nixon, Pence continued: “What’s evident from the notes, what’s evident from all of the revelations over the last several weeks is that Hillary Clinton operated in such a way to keep her emails, and particularly her interactions while secretary of state with the Clinton Foundation, out of the public reach, out of public accountability.”

He added: “I think it all just … it all truly does disqualify her from serving as president of the United States.”

Clinton has been dogged for more than a year by the fallout from her decision to use an unauthorized private email account run from the basement of her home in Chappaqua, New York. She repeatedly said she did not use it to send or receive classified information. The government forbids handling such information outside secure channels.

Contradicting Clinton’s comment that she never exchanged classified information over her private email server, the FBI said that at least 81 email threads contained information that was classified at the time, and said the final number may be more than 2,000.

Clinton has said that in hindsight she regretted using a private email system while secretary of state. Opinion polls show that voter concerns about Clinton’s honesty and trustworthiness are among her biggest vulnerabilities.

A series of surveys show the race has tightened over the past few weeks. In a Reuters/Ipsos poll taken during the week of 26 August to 1 September, Trump had the support of 40% of likely voters while Clinton had the backing of 39%. Clinton’s support has dropped steadily in the weekly tracking poll since 25 August, eliminating what had been a eight-point lead for her.

According to the head-to-head realclearpolitics.com poll average, Clinton retains a 3.9% lead over Trump. In the four-way split, including Libertarian Gary Johnson and the Green Party candidate, Jill Stein, she leads by 3.4%. Johnson, a former Republican governor of New Mexico, is at 8.2%.

A CBS poll released on Sunday put Clinton two points ahead in “all states that may be in play or could come into play this fall depending on the race, 13 in total”.