Aides who handled Boston City Hall's tourism and intergovernmental relations portfolios pled not guilty Tuesday to federal charges they extorted a music festival early in Boston Mayor Marty Walsh's administration.

Without naming the festival in the indictment, federal prosecutors in the office of U.S. Attorney Carmen Ortiz accused the top aides to Boston Mayor Marty Walsh of extorting Boston Calling, making the organization hire union stagehands before awarding permits for the September 2014 music fest.

Tim Sullivan, chief of staff for intergovernmental relations, and Kenneth Brissette, director of Tourism, Sports and Entertainment, appeared before Magistrate Judge Judith Dein on Tuesday to answer the charges in a June 28 indictment. The arraignment was brief without delving into the facts of the case or arguments from either side.

"Nothing today," Tom Kiley, an attorney for Sullivan told reporters after exiting the courtroom. Bill Cintolo, Sullivan's other attorney, deferred comment to Kiley.

Assistant U.S. Attorney Laura Kaplan told the court she anticipated the prosecution's case would take about two weeks if it goes to trial. The charges carry maximum penalties of 20 years imprisonment.

Federal sentences, which would follow a guilty plea or conviction, generally vary depending on circumstances surrounding the alleged crime and the defendants.

Both Sullivan and Brissette were part of Walsh's administration before they were arrested this spring and summer, and both are on paid leave, the mayor has said.

Dressed in suits, the two men told Dein they understood the charges and pled not guilty.

William Kettlewell, Brissette's attorney told Dein there is a "fair amount" of discovery to be made in the case, and Dein gave the defense attorneys until Aug. 8 to make their discovery requests. The next status conference will be held Aug. 18, Dein said.

Kiley also told the magistrate there is a motion "under seal" that he plans to respond to by Aug. 8.

Sullivan and Brissette each face one count of extortion and one count of conspiracy to commit extortion. A former top official in the Boston Building Trades, Walsh has expressed some concern at the allegations in the indictment while adamantly maintaining there was no directive for City Hall to tell outside groups to hire union labor.

Dein, who recently received the case, said she would keep jurisdiction over it for some time.

"You've met most of the magistrate judges in this case, but you're actually here for a while," Dein said.