CHICAGO (AP) - People attending this year's Lollapalooza music festival in downtown Chicago are finding stricter rules and stepped-up security.
The four-day event began Thursday. Headliners include Bruno Mars, Jack White and the Arctic Monkeys.
Chicago police say they've increased security partly because of the October mass shooting at a Las Vegas music festival, where a gunman killed 58 people from a 32nd-floor hotel suite. Authorities have said he also booked rooms overlooking last year's Lollapalooza but didn't show up.
Police closed more roads and put up additional barriers around this year's Lollapalooza. They've also been in contact with hotels and other businesses and properties surrounding Grant Park, and will be monitoring rooftops and shining lights into hotel rooms.
Attendees aren't allowed to bring backpacks this year and are going through airport-style screening.