In a statement Wednesday Tutu says two of the hikers are ill and they are all suffering emotionally and are considering a hunger strike. He says Shane Bauer, Josh Fattal and Sarah Shourd have committed no crime.
The three Americans have been held since crossing the border from Iraq in July. Their families say they unintentionally strayed while hiking.
They all attended the University of California at Berkeley.
Fattal's family lives near Philadelphia, Bauer's in Pine City, Minnesota, and Shourd's in Oakland, California.
Tutu, a Nobel Peace Prize laureate, is the former head of the Anglican Church of Southern Africa.