A skydiving plane with 15 people aboard went off the end of a runway in southern New Jersey on Wednesday evening, federal authorities said. A number of casualties have been reported.

A downed aircraft near Cross Keys Airport in Williamstown, New Jersey, has prompted a "mass casualty incident," Gloucester County Emergency Management said Wednesday. The officials added, "Please avoid the area to allow emergency vehicles the best access!"

The plane, a Cessna 208B, went off the end of a runway as it was taking off from a small airport in Gloucester County, according to the F.A.A. Victims were being treated at the scene, officials said.