HOUSTON, May 12 (Xinhua) -- At least 17 people were injured Sunday when gunmen opened fire at a parade in New Orleans in the U. S. state of Louisiana, U.S. media reported.

None of the injuries was believed to be life-threatening, cnn quoted police spokeswoman Remi Braden as reporting.

"This is an extremely unusual occurrence, and we're confident that we will make swift arrests," Braden said. It appeared "two or three people," for an unknown reason, started shooting at the crowd, police Superintendent Ronal Serpas said.