ST. LOUIS - Two people injured when pyrotechnics went awry at Beyonce Knowles' concert in St. Louis received a surprise emergency room visit from the singer.

The accident happened Sunday night, just as the R&B star's concert began. A spokeswoman for Scottrade Center didn't return phone calls seeking comment, but broadcast reports said pyrotechnics meant for the stage accidentally spilled into the front row.

Two concertgoers were taken to Barnes-Jewish Hospital. Spokeswoman Kathy Holleman wouldn't release their names but said the injuries were minor. Both were expected to make a full recovery.

Soon after the concert, Knowles arrived at the hospital, said head nurse Darryl Williams.

"She was just very concerned about the people injured in the audience," Williams said. "It was unannounced and we kept it very low-key so that she could spend time with them."

Knowles, 25, met with the fans for about 45 minutes. "I just thought it was a great thing for someone of her stature to do," Williams said.

A spokesman for Houston-based Music World Entertainment, which represents Knowles, declined comment.

Knowles' world tour opened in April in Tokyo and runs through early September. Other stops include New Orleans, Dallas, New York City, Washington, Boston, Chicago, Denver, Las Vegas and Los Angeles.

She won a Grammy Award in February for contemporary R&B album for "B'Day," her second solo album. Knowles won five Grammys for her solo debut, 2003's "Dangerously in Love." She previously fronted R&B girl group Destiny's Child.

Knowles starred in the 2006 movie "Dreamgirls."