There's no question Beyoncé's rendition of the national anthem was a roaring success. The mystery: was it live or lip-synced?

On Tuesday, a spokeswoman for the U.S. Marine Band told news outlets that Beyoncé had lip-synced at President Barack Obama's inauguration. Master Sgt. Kristin duBois said the band was notified at the last minute that Beyoncé would use a pre-recorded voice track.

But by late afternoon, the marine corps backed off that statement.

Marine corps spokesman Capt. Gregory Wolf said that because there was no opportunity for Beyoncé to rehearse with the Marine Band, it was determined that a live performance by the band was ill advised. Instead they used a pre-recorded track for the band's portion of the song.

"Regarding Ms. Knowles-Carter's vocal performance," Wolf's statement continued, "no one in the Marine Band is in a position to assess whether it was live or pre-recorded."

A representative for Beyoncé did not respond to requests for comment.

DuBois declined to answer further questions. Earlier in the day, she told the New York Times that the rest of the inaugural performance was live and they did not know why a recorded track was used for the national anthem.

"It's not because Beyoncé can't sing. We all know Beyoncé can sing. We all know the Marine Band can play," she said.

Kelly Clarkson's representative said she sang live to perform My Country, `Tis of Thee.

Inaugural organizers did not respond to requests for comment.

All inaugural music is pre-recorded in case weather conditions or other circumstances could interrupt the program.

The use of a recording is typical in big events. In 2009, cellist Yo-Yo Ma was questioned about "hand-syncing" for Obama's first inauguration. Ma said instruments weren't functioning properly in 7 C weather.

Even in good conditions, producing good sound can be a challenge in a large open space.

Some artists choose to lip-sync. Whitney Houston's memorable performance of the national anthem in 1991 at the Super Bowl was sung to a track.