Some Madonna fans in Colorado have complained after the music superstar used guns during a performance.
A gunman shot dead 12 people during a Batman film at cinema in the state in July.
Madonna started her show at the Pepsi Centre in Denver with a gun scene, which she has used in previous performances.
KUSA-TV said it received several calls from concert-goers saying they were offended she used guns and violence as part of her show in light of recent events.
In a statement before beginning the tour, Madonna said she does not condone the use of guns. She said she is using the guns as symbols of intolerance and "the pain I have felt from having my heart broken."