Though the FBI found that Hillary Clinton and her staff were “extremely careless” with State Department emails hosted on a private server, no criminal charges will be brought against the former secretary and current presidential candidate.

“No reasonable prosecutor” would bring criminal charges in this case, FBI Director James Comey told reporters Tuesday morning, after going into the details of the bureau’s two-year investigation, which he described as a “painstaking undertaking requiring thousands of hours of effort.”

“Three of those were classified at the time,” he added.

Clinton used “several different serversand numerous mobile devices” to send and read emails on her personal domain during her tenure as secretary of state from 2009 to 2013, Comey explained. The FBI set out to investigate any intentional or grossly negligent handling of classified information, as well as whether any hostile actors gained access to the files, after the intelligence community Inspector-General requested a probe.

Of the 30,000 emails turned over to the State Department, the FBI found that 110 messages in 52 chains contained information that was classified at the time, of which eight were Top Secret, 36 were Secret and eight were Confidential. Another 2,000 messages were later deemed to have contained classified information based on their subject matter, in a process called “up-classification.”

WATCH LIVE: 110 emails on Clinton's private server contained classified material- Comey https://t.co/aQNiMZ7dkKpic.twitter.com/wq4EXQD4iK — RT America (@RT_America) July 5, 2016

The FBI also found “several thousand” work-related emails that had been deleted over the years. Three of those were classified at the time. However, the bureau concluded that none of them were intentionally deleted to hide information, Comey said.

Though he said that Clinton’s lawyers “cleaned” the devices used to host the email servers in a way that precluded further forensic discovery before turning them over to the bureau, the FBI is confident “there was no intentional misconduct,” according to Comey.

No direct evidence was found that Clinton’s personal domain was hacked successfully, but hostile actors could have gained access at some point, given the lack of support and protection of the private servers, he said.

“None of these emails should have been on any kind of unclassified system,” Comey said, adding that Clinton and her associates were “extremely careless” in handling highly classified information, while “the security culture at the State Department was generally lacking.”

Even so, the FBI chief announced that he would not recommend any criminal charges be pressed against the former secretary, who is the presumptive Democratic nominee for the US presidency.

“No reasonable prosecutor would bring such a case,” he said.

On Friday, Attorney General Loretta Lynch announced that she would accept the bureau’s recommendations in the Clinton email probe, whatever they might be. Lynch was defending her 40-minute private meeting with former President Bill Clinton at the Phoenix, Arizona airport, which she said involved discussions about golf and grandchildren, and in no way touched upon the email probe.

The FBI investigation was done “honestly, competently and independently,” with no outside influence, Comey said on Tuesday. “Only facts matter. And the FBI found them here in an entirely apolitical and professional way.”

While the State Department would not comment on the FBI decision, spokesman John Kirby took exception to Comey’s characterization of the security culture at Foggy Bottom as “generally lacking.”

“We don’t share that assessment of our institution,” Kirby told reporters Tuesday afternoon, adding that the State Department takes security “very seriously” and “will continue to look for ways to improve.”

The Clinton campaign said it was pleased with the FBI’s announcement.

“As the Secretary has long said, it was a mistake to use her personal email and she would not do it again. We are glad that this matter is now resolved,” campaign spokesman Brian Fallon said.