The U.N.'s top human rights official has expressed alarm at the death sentence imposed on an alternative health practitioner in Iran.

The U.N. human rights office says Mohammad Ali Taheri was sentenced to death Saturday after being found guilty of "corruption on Earth."

Zeid Raad al-Hussein, the U.N. high commissioner for human rights, said in a statement Wednesday that the death sentence against Taheri illustrates Iran's "problematic" application of the death sentence for lesser crimes and for crimes committed by minors.

Zeid said he calls on Iranian authorities to "immediately withdraw the charges against Taheri and ensure his unconditional release."

Zeid's office says Taheri is the founder of a spiritual movement, practicing alternative medicine theories used in Iran and elsewhere.