Washington (CNN) Missouri GOP Gov. Eric Greitens was indicted on Thursday amid looming allegations of sexual misconduct and blackmail following an admission of an affair last month.

He was charged in St. Louis with a first-degree felony invasion of privacy, according to the Missouri court system

In a statement Thursday, Greitens denied committing any crime and instead called the situation "a personal mistake" from his time prior to taking office.

"As I have said before, I made a personal mistake before I was Governor. I did not commit a crime," his statement read. "With today's disappointing and misguided political decision, my confidence in our prosecutorial system is shaken, but not broken. I know this will be righted soon. The people of Missouri deserve better than a reckless liberal prosecutor who uses her office to score political points. I look forward to the legal remedies to reverse this action. This will not for a moment deter me from doing the important work of the great people of Missouri."

CNN affiliate KMOV published a report last month where a man said his now-former wife had an affair with Greitens in 2015. The report included details of a recording of a woman saying Greitens had tried to blackmail her to keep quiet about their sexual encounter.

Greitens denied he resorted to blackmail, but admitted to an affair, and the circuit attorney for St. Louis, Kimberly M. Gardner, said they had launched a formal investigation.

In a statement, Gardner said the alleged incident took place in March 2015 and vowed to "hold public officials accountable in the same manner as any other resident."

Greitens' attorney, Edward Dowd Jr., said in an email to KMOV : "In forty years of public and private practice, I have never seen anything like this. The charges against my client are baseless and unfounded. My client is absolutely innocent. We will be filing a motion to dismiss."

Susan Ryan, a spokeswoman with the Circuit Attorney's Office released a statement saying the governor's lawyers had requested a "secret" meeting with her office prior to the indictment as they wanted to share the "human" side of Greitens' story.

"The Circuit Attorney makes charging decisions based upon facts and evidence. Without additional facts and information from the Governor, the meeting was not necessary," Ryan said.

In response to the "governor's personal attacks," Ryan said, her office "believes the courtroom is the appropriate place to argue the facts, not the media."

The indictment alleges Greitens took a picture of a person in "full or partial nudity" without the person's knowledge or consent, and that Greitens then transmitted the image "in a manner that allowed access to that image via a computer."

Gardner's statement said the transmission of the image in such a manner is a felony under the privacy statute Greitens is accused of violating.

Missouri House Speaker Todd Richardson, Floor Leader Rob Vescovo and Speaker Pro Tem Elijah Haahr released a statement on the indictment, announcing they have begun an investigation into the matter.

"We will carefully examine the facts contained in the indictment, and answer the question as to whether or not the governor can lead our state while a felony case moves forward," their statement read. "The people of Missouri deserve no less. We will begin the process of tasking a group of legislators to investigate these serious charges."

Additionally, Greitens is no longer planning to travel to Washington, DC, to participate in Republican Governors Association events Friday, according to a source familiar with the matter.

Vice President Mike Pence is scheduled to host a luncheon for the Council of Governors meeting Friday.

Al Watkins, the lawyer representing the ex-husband, said his client hopes to "put things in the rearview mirror" and move on.

"Lady justice can sometimes operate in cumbersome ways," Watkins said. "But right now we have an individual charged with a felony, and in our great land, one must presume innocence until guilt has been proven beyond a reasonable doubt. It's best to let the system take its course."