Then the 53-year-old told the U.S. audience: "Don't get fat and lazy and take that freedom for granted."
Madonna kicked off her concert late on Tuesday, apologizing to the crowd, who began to boo before she hit the stage around 10:30 p.m. EST.
"We had many changes to make from Europe to America, and I wanted the show to be perfect for you because my fans deserve it and quite frankly I deserve it," she said.
She performed for nearly two hours, starting in a skin-tight black ensemble with a gun in hand as she sang the song "Girls Gone Wild" from her latest album "MDNA." She transitioned to "Revolver," as she and her background dancers held guns and bullets appeared on the backdrop. (Madonna posted on her website that she does not condone violence or the use of guns and she's using fake guns in concert as a metaphor for strength.) During the next song — "Gang Bang" — she shot a man and spat what appeared to be liquor in his face, while blood spats and bloody hands appeared on the screen.
The dark mood escaped as Madonna changed into a red and white marching band get-up, singing "Express Yourself" and "Give Me All Your Luvin'" as a marching band played to the crowd. She sang some of Lady Gaga's "Born This Way," pulling up her skirt to reveal her red shorts.
Madonna's performances of "Celebration" and "I'm Addicted" were also colorful, as laser lights beamed and the venue became nightclub-like. Madonna's best vocal performance, though, was during "Like a Prayer," which featured more than 30 back-up singers in robes. She got the best response from the crowd when she performed "Vogue," as the dancers and Madonna — now in a corset, long gloves and her hair pulled back — strutted in black and white onstage.
She got racy during "Like a Virgin" and "Human Nature," taking off her shirt to reveal her bra, and pulling down her pants to reveal her thong (she wore fishnet stockings).
"Sometimes it's easier to show your (butt) than show your feelings. Maybe tonight we can all live dangerously," said Madonna, who had the words "No Fear" on her back.