Hillary Clinton broke government rules by using a private email server without approval for her work as U.S. secretary of state, an internal government watchdog said on Wednesday.
The long-awaited report by the State Department inspector general was the first official audit of the controversial arrangement to be made public. It was highly critical of Clinton's use of a server in her home, and immediately fueled Republican attacks on Clinton, the Democratic front-runner in an already acrimonious presidential race.
The report, which also found problems in department record-keeping practices before Clinton's tenure, undermined Clinton's earlier defenses of her emails, likely adding to Democratic anxieties about public perceptions of the candidate. A majority of voters say Clinton is dishonest, according to multiple polls.
The report concluded that Clinton would not have been allowed to use the server in her home had she asked the department officials in charge of information security. The report said that staff who later raised concerns were told to keep quiet. Several suspected hacking attempts in 2011 were never reported to department information security officials, in breach of department rules, it said.
"She's as crooked as they come," Donald Trump, the presumptive Republican presidential candidate, said of Clinton at a campaign rally in Anaheim, California, adding that the report's findings were "not good" for her. Clinton's campaign disagreed, saying the report rebutted Republican's criticism.
The inspector general's office examined email record-keeping under five secretaries state, both Democratic and Republican. John Kerry, the current officeholder, and predecessors Madeline Albright, Colin Powell and Condoleezza Rice all agreed to speak to the inspector general's investigators. Clinton was the only one who declined to be interviewed, as did her aides.
The report contradicted Clinton's repeated assertion that her server was allowed and that no permission was needed.
Several other inquiries continue, including a U.S. Justice Department investigation into whether the arrangement broke laws.
The inspector general's report cited "longstanding, systemic weaknesses" with State Department records that predated Clinton's tenure, and found problems with the email record-keeping of some of her predecessors, particularly Powell, that failed to comply with the Federal Records Act.
But it singled out Clinton for her decision to use a private server in her home in Chappaqua, New York, for government business.
"OIG found no evidence that the Secretary requested or obtained guidance or approval to conduct official business via a personal email account on her private server," the report said, using an abbreviation for the office of inspector general.
The report said Clinton should have discussed the arrangement with the department's security and technology officials. Officials told investigators that they "did not - and would not - approve her exclusive reliance on a personal email account to conduct Department business." The reason, those officials said, is because it breached department rules and presented "security risks."
State Department spokesman Mark Toner said he would not "challenge" those findings. He told reporters the department was aware of hacking attempts on Clinton's server, but had no evidence that any were successful.
When two lower-level information technology officials tried to raise concerns about Clinton's email arrangement in late 2010, their supervisor in Clinton's office instructed them "never to speak of the Secretary's personal email system again," the report said. Their supervisor told them that department lawyers had approved of the system, but the inspector general's office said it found no evidence this was true.
Brian Fallon, a Clinton spokesman, said the report rebutted criticisms of Clinton made by her political opponents.
"The report shows that problems with the State Department's electronic recordkeeping systems were longstanding and that there was no precedent of someone in her position having a State Department email account until after the arrival of her successor," he said in a statement.
He did not address the report's criticism of Clinton's use of a private server, something no other secretary of state has done.
Democrats, including fundraisers for Clinton's campaign, said the report revealed nothing new.
"It's digging and digging and digging," Amy Rao, the chief executive of data company Integrated Archive Systems and a Clinton fundraiser, said in an interview, comparing the investigation to probes the Clintons faced in the 1990s. "Trust me: There's no there there. It's Whitewater."
Current Secretary of State Kerry asked Steve Linick, the State Department inspector general, to investigate after Clinton's email arrangement came to light last year. President Barack Obama appointed Linick to the role in 2013.
Republicans have used Clinton's email practice to suggest she was trying to hide government records from scrutiny under public-access laws.
Republican National Committee Chairman Reince Priebus said in a statement that the findings "are just the latest chapter in the long saga of Hillary Clinton's bad judgment that broke federal rules and endangered our national security."