In the wake of fierce criticism over the investigation of Hillary Clinton's private email server and release of related documents, FBI Director James Comey issued an internal memo Wednesday to employees regarding the agency's "commitment to transparency" while also taking time to hit back at critics.

Comey defended the bureau's release on Friday of documents from the Clinton server investigation, writing "we don't play games."

"I almost ordered the material held until Tuesday because I knew we would take all kinds of grief for releasing it before a holiday weekend, but my judgment was that we had promised transparency and it would be game-playing to withhold it from the public just to avoid folks saying stuff about us," Comey wrote.

He added the FBI is continuing to process additional material, and will release documents as they are ready, "no matter the day of the week."

Comey also described Clinton's case as "not a cliff-hanger."

"At the end of the day, the case itself was not a cliff-hanger; despite all the chest-beating by people no longer in government, there really wasn't a prosecutable case," Comey wrote. "The hard part was whether to offer unprecedented transparency about our thinking. I explain to our alumni that I struggled with that part, but decided the best way to protect the FBI, the Department of Justice, and the American people's sense of justice was to announce it in the way we did - with extraordinary transparency and without any kind of coordination."

The FBI director said he will be testifying at the House Judiciary Committee during the last week of September as part of the regular annual oversight hearing.

"This is our regular annual oversight hearing, so I'm hoping to cover many aspects of the Bureau's great work," he wrote. "Of course, I'm guessing folks will want to ask about the email investigation."

He also took time to hit back at those critical of the bureau's investigation into Clinton.

"I explain to our alums that I'm okay if folks have a different view of the investigation (although I struggle to see how they actually could, especially when they didn't do the investigation), or about the wisdom of announcing it as we did (although even with hindsight I think that was the best course), but I have no patience for suggestions that we conducted ourselves as anything but what we are - honest, competent, and independent. Those suggesting that we are "political" or part of some "fix" either don't know us, or they are full of baloney (and maybe some of both)," he wrote.

He concluded the memo with writing, "I will try not to bother you with this any longer."