GENEVA (AP) — The United Nations human rights office says U.S. death row inmate Clayton Lockett’s suffering during his botched Oklahoma execution this week may amount to cruel, inhuman and degrading treatment under international human rights law.

A spokesman for the office, Rupert Colville, says Lockett’s prolonged death on Tuesday is “the second case of apparent extreme suffering caused by malfunctioning lethal injections” reported in the United States this year, after Dennis McGuire’s execution in Ohio on Jan. 16 with an allegedly untested combination of drugs.