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

The accident happened Sunday night, just as the R&B star's concert began. A spokeswoman for Scottrade Center did not 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 would not release their names but said the injuries were minor. Both were expected to make full recoveries.

Soon after the concert, Knowles, 25, showed up unexpectedly, said Darryl Williams, head nurse at the hospital.

"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 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 Grammy Awards for her top-selling solo debut, 2003's "Dangerously in Love." She previously fronted the R&B girl group Destiny's Child.

She also starred in the movie "Dreamgirls," and also had roles in the comedies "The Pink Panther" and "Austin Powers in Goldmember."