Updated at 10:48 p.m.: Police said at midday that the campaign has issued nearly 20,000 free tickets.

Donald Trump’s presidential campaign has given out more than 18,000 free tickets for his appearance Thursday night at the 1,400-seat Flynn Center for the Performing Arts, Burlington Police Chief Brandon del Pozo said Wednesday.

Del Pozo said that the large gap between tickets issued and seats available is a problem.

“We’re working with the campaign to see what their plans are to accommodate people who don’t have tickets,” del Pozo said. As of Wednesday afternoon, the campaign had not offered any indication it had any such plans. The city has no plans to cancel the event, del Pozo said.

Asked if Trump’s campaign had been cooperative in planning for the overflow, del Pozo said, “They’re cooperative when it comes to a safe event inside the Flynn. They consider what happens outside the theater as the province of police and public safety agencies rather than the campaign.”

The city is planning to close streets around the Flynn and bring in extra patrols in response both to the possible overflow of attendees and to planned protests. Del Pozo said lower Church Street between Main and King streets will be closed to traffic and parking starting at noon Thursday.

Main Street from Church to St. Paul Streets will be closed to traffic and parking starting at 1 p.m., he said. Protesters plan a rally at City Hall Park and a vigil at St. Paul and Main streets in response to Trump’s 7 p.m. appearance at the Flynn.

The event originally was planned for only the 1,000-seat main floor space of the Flynn, but based on the large number of tickets being issued, balcony seats were added Tuesday, Flynn Executive Director John Killacky said. That brings the seating total to about 1,400.

Trump’s campaign has been issuing free tickets via the online site EventBrite. Shortly after tickets became available, the site indicated the event was sold out, but that quickly changed and tickets remained available Wednesday afternoon, even after local officials expressed concern about the gap between the number of tickets and seats.

Some Trump opponents have indicated in online discussions that they were acquiring tickets, but then planned not to use them, hoping it would leave empty seats at the theater. The strategy will not likely have that effect, given the large number of tickets issued, but it means no one knows how many people who acquired tickets will actually try to use them.

Killacky said doors will open at 5 p.m. Secret Service will be screening event-goers, and Trump goes on stage at 7 p.m. sharp. If seated attendees leave the theater in protest, no new attendees will be let in, he said.

Del Pozo said police will be patrolling outside, at what he described as a significant overtime cost to the city. If those who get shut out have complaints, he will refer them to the Trump campaign. He offered this advice to attendees: “If you come, don’t expect to get in.”