Pop star Hilary Duff is hitting back at reports she was caught lip-syncing during a concert in Mexico on Saturday, insisting "faulty equipment" sparked the misunderstanding.

The singer was caught bending over her microphone and silently singing into it as part of concert footage posted on website YouTube.com. But her representatives insist the microphone was faulty and she could clearly be heard singing by fans at the front of the stage.

One aide says, "There was no sound coming out, but she was singing."

People.com reports Duff was using venue-provided sound equipment rather than her regular gear, and her microphone was inadvertently set to mute for the first few seconds of her performance.

-Hilary Duff Pictures

(This news article provided by World Entertainment News Network)