Someone armed with a BB gun shot at people near a nursery school in the French city of Lyon on Friday, slightly injuring 11 adults but no children, the city's public prosecutor said.

Police surrounded the area, but prosecutor Xavier Richaud told reporters that initial attempts to locate the shooter or find out where the 4.5 mm shots originated proved fruitless.

The shooting 30 yards from the Harmony nursery school took place just as parents were collecting their children before the lunch break. Some mothers were "very lightly injured on their arms and legs," Richaud said.

A police officer from an emergency response team that was among the first on the scene was also hit in the leg. Richaud said the firing ceased after the officer was hit.

It was not immediately clear how many shots were fired, he said.

Of the 11 people hit, three were taken to the hospital and immediately released, Richaud said.

The prosecutor said police had not yet developed a profile of the shooter.

"There are not witnesses, no one saw the shooter," he said. "It's certainly someone who is not a bad shot because it was windy."

Anne Le Scanff, spokeswoman for the Lyon school district, said the shooter was not aiming at the school.

"The children were in class ... they weren't aware of what happened," Le Scanff said. "The situation is under control."

The school's afternoon session was canceled.