A half-dozen razor blades were planted in a park lawn next to Bonita Cove with the apparent intention of cutting people, and one woman's foot was cut, San Diego lifeguards said.
The 41-year-old victim got a cut to the side of one of her feet while walking on the turf near a playground alongside Mission Bay, San Diego lifeguard Lt. Rick Strobel said.
Lifeguards treated her at the scene, Strobel said. She did not require hospital care.
City personnel cleared visitors out of the area and searched it, finding other razor blades that apparently had been pushed into the grassy ground, sharp side up.
No suspects were identified.
The same type of razor booby-trapping of local parks has happened on prior occasions, leading to injuries, Strobel noted. The grassy area is near a playground and is heavily used.