Ohio has postponed all six of its scheduled executions this year until 2016 as it tries to find supplies of drugs to use in lethal injections.

The move by the state Department of Rehabilitation and Correction Friday comes amid controversy over how states execute those sentenced to death. The U.S. Supreme Court recently agreed to take up a legal challenge to Oklahoma's method. The execution dates for inmates scheduled to die in 2016 remained unchanged, the department said in a statement.

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Some states have been struggling to find drugs to execute inmates by lethal injection after manufacturers of the drugs that had been used in the past stopped selling them for the purposes of putting people to death.

Ohio this month scrapped an execution-drug combination it had used when it put Dennis McGuire to death in January of 2014. McGuire was put to death with midazolam and hydromorphone, and the convicted rapist and murderer appeared to gasp during the 26 minutes it took him to die. The state said it would switch to pentobarbital and sodium thiopental, but since manufacturers refuse to sell it for executions, states have to take the more difficult route of obtaining the drugs from compounding pharmacies.

Ronald Phillips had been the next Ohio inmate sentenced to die before the executions were pushed back. Phillips, convicted of raping and murdering a 3-year-old, was scheduled to be executed on Feb. 11. His execution was rescheduled for Jan. 21, 2016, according to the department.

The Supreme Court this week agreed to hear a challenge brought by three death-row inmates in Oklahoma who argue that the three-drug combination the state uses in executions is unconstitutional.

IN-DEPTH

— Phil Helsel