(CNN) Efforts to hold a " Straight Pride Parade " in Boston are one step closer to becoming reality.

City officials said the organizers' public event application was approved Thursday, the first step toward receiving a permit for the parade.

Next, organizers need the approval of police district captains and the licensing board to receive a parade permit and an entertainment license.

More than 350 volunteers have joined the effort and Milo Yiannopoulos is slated as the grand marshal, he said. The permit says 2,000 attendees are expected.

"The city has assured me that if we follow the steps, it will go through," said Hugo, whose name is on the event application as the primary organizer.

If it goes forward, Mayor Marty Walsh will not attend, city officials said.

The parade would be held on August 31 from noon to 3 p.m., according to the application. It would start on Boylston and Clarendon Streets and proceed along Boylston to Tremont.

The mayor's office emphasized that event applications are granted "based on operational feasibility" and not "values or endorsements of beliefs."

The group originally requested to hold the event on City Hall Plaza and raise the "Straight Pride Flag" on city hall flag poles, the office said in a statement.

According to the organizers' website , the straight pride flag features the male and female sex symbols linked against a purple and blue background.

The request to raise the flag was "respectfully denied" since use of the poles "is at the city's sole and complete discretion," the statement said.

"The city maintains that its flag poles are a forum for government speech. As such, the city maintains selectivity and control over the messages conveyed by the flags flown on our flag poles, and has chosen not to display the 'Straight Pride' flag."