Dog treats filled with fishing hooks found on the Appalachian Trail in Penn.

A hiker came across suspicious dog treats on the Appalachian Trail — and now authorities are warning dog owners to be careful.

The Pennsylvania Game Commission and the Lehigh Gap Nature Center shared on social media on Monday, May 6, that a hiker found dog treats “filled with fishing hooks” while hiking along the Appalachian Trail.

The treats were found near the North Trail Loop, where the trail leads to the George W. Outerbridge shelter in Washington Township, Pennsylvania. This section of trail connects to the Lehigh Gap Nature Center trail system via the Woodpecker Trail, according to the Lehigh Gap Nature Center.

The Pennsylvania Game Commission shared photos of the dangerous dog treats the hiker found. The treats appear to have a hard shell filled with a soft filling; inside the filling, the treats have several fish hooks stuffed inside.

In one photo, a treat is broken in half and several twisted metal pieces protrude from the flesh-colored center.

Officials did not say how many treats were found with fish hooks in them, but based on the photos, at least a handful were discovered in the area.

The Lehigh Gap Nature Center noted that all hook-filled treats in the area had been “removed.” The center also encouraged hikers with pets to exercise “caution” on the Appalachian Trail “around the Lehigh Gap.”

The Pennsylvania Game Commission warned on Facebook that the treats “could prove fatal to any animal that consumes them, including wild and domestic animals.”

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According to PetCoach, which offers dog owners advice from veterinarians and other pet experts, putting a fish hook in its mouth can cause “drooling, clawing, or difficulty swallowing” for dog owners. If a dog swallows a fishing hook and gets stuck in the esophagus or stomach, it can cause a dog to gag, gag, vomit, stop eating, drool, have difficulty swallowing, or experience weight loss or dehydration.

PetCoach noted that a fishing hook can be “difficult to remove without causing tissue damage” because the barbs can become “deeply lodged” in the tissue it comes into contact with.

The Pennsylvania Game Commission said people should file a report if they see more of these noxious treats on the Appalachian Trail by calling 1-888-PGC-WILD or 1-888-PGC-HUNT.