A top official in Boston Mayor Martin Walsh’s administration pleaded not guilty on Thursday to a corruption charge that could lead to a maximum of 20 years in prison.

Kenneth Brissette, the city’s director of tourism, sports, and entertainment, was arrested for allegedly withholding city permits from a music festival until union workers were hired to staff the event in 2014.

A federal indictment released Thursday outlined allegations that Brissette had engaged in union-related extortion.

The Boston Globe reported "federal authorities were investigating whether Brissette had pressured organizers of Boston Calling, a biannual festival held at City Hall Plaza, to use union labor."

The festival, which was held in September 2014, had originally employed non-union workers.

Brissette allegedly withheld the permits until festival organizers hired union workers from the International Alliance of Theatrical Stage Employees, Local 11. Three days before the opening, Boston Calling entered a contract and hired Local 11 laborers. The necessary permits were not granted to the festival until afterward.

Brissette and Walsh contend that the city did nothing illegal, although at least one other City Hall employee reportedly urged the festival to hire union workers. The firm representing Brissette called the indictment "factually and legally flawed."

In a statement released after the indictment, Walsh said he is "deeply concerned about today’s news."

"Everyone who knows Ken knows him to be a good and hardworking person. We will continue to work with the U.S. Attorney’s Office to get to the bottom of this," he said.

This is not the first time Brissette has been linked to alleged union intimidation tactics. In 2014, Brissette allegedly warned restaurants that Teamsters members planned to disrupt filming of the reality TV show Top Chef, which had hired non-union labor. The resulting disruption led to five charges of extortion against Teamsters members. Brissette was not charged in the incident.

Brissette has been released from jail on a $25,000 bond and has been placed on paid on administrative leave from his job with the city. The case will continue until July 12.