SALT LAKE CITY (AP) — Concertgoers can expect more security personnel and other changes after a larger-than-expected crowd at the summer's first Twilight event in Salt Lake City.

Police estimate 40,000 people jammed Pioneer Park on Thursday night for the concert by the band Modest Mouse, about 10,000 more than expected.

"We're still very concerned with trying to make sure it's a safe and comfortable experience for people, and last night that was certainly pushed to the limit," Salt Lake City Mayor Ralph Becker said Friday. "Even though we had a lot of extra security there, I know that today everyone is reassessing what we need to do."

Casey Jarman, director of the summer concert series, said while the 50 to 60 security personnel were sufficient to handle the crowd, the city will hire more guards to make the event as enjoyable as possible.

Some concertgoers knocked over temporary fences on a corner of the park, and guards also will be distributed to prevent fence-jumping.

Jarman said the City Arts Council, which organizes the concert series, also will consider ways to get people into the park faster and to keep food and beer lines from blocking pedestrian paths.

This is the first year the Twilight series has taken place at Pioneer Park. The concerts were moved from the Gallivan Center, where attendance averaged 16,000 a show last year, because of a massive renovation project. The Twilight series could return there in 2011.

Feedback about Thursday's show from concertgoers was "phenomenally positive," Jarman said.

But Kyong Millar, a regular at the Twilight shows, said the show was "a miserable experience."

"I think they need to cap (attendance)," Millar said, saying too many people were crowded into the park and many of them weren't there for the music.

Businesses near Pioneer Park reported strong business Thursday night.