OGLESBY, Ill. (AP) — Illinois conservation officials are cautioning hikers to stay on marked trails after three hikers fell in or near Starved Rock State Park in recent weeks.

Officials say all three hikers moved off marked paths and climbed sandstone walls before falling and needing rescue.

Illinois Conservation Police Officer Phil Wire is one of four conservation officers stationed in LaSalle County. He says the area is comprised of St. Peter sandstone, which looks solid but actually is fragile and can crumble under a person's feet.

Officials warn that hiking off-trail not only is dangerous, but also can be costly. The Chicago Tribune reports that people who are retrieved by rescue crews at Starved Rock could receive a bill for emergency services and perhaps face citations for entering a restricted area.

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