Razor blades, bent forks and other sharp items were found wedged into playground sand and equipment at a park in the small town of Oro Grande near Victorville, officials said.
Maintenance employees discovered the sharp objects at Oro Grande Park at about 9 a.m. Tuesday during an inspection at 3rd and Meyer streets, according to the San Bernardino County Sheriff's Department.
Authorities said the sharp items were hidden in the sand, while blades were wedged into playground equipment with the "intent to conceal the dangerous items so they would injure the children."
Although no arrests have been made, sheriff's officials said the incident appears to be isolated.
Still, authorities said they did not receive any threats against children at the park.
The discovery prompted a warning from the San Bernardino County Sheriff's Victor Valley Station to parents.
Parents were asked to look out for any sharp objects at local parks, and for help in identifying potential suspects.
"We need to protect our children and we need anyone who has information regarding this serious crime to come forward," Sgt. Jim Evans said in a statement. "We are thankful to park employees for doing a thorough inspection of their facilities and locating these dangerous items before a child was injured."