The Supreme Court has ordered Oklahoma to postpone lethal injections executions using a controversial sedative until the court rules in a challenge involving the drug.

The court's order Wednesday came as little surprise after both the state and the lawyers for three inmates who faced execution between now and March requested the temporary halt. The justices agreed on Friday to take up the challenge to the use of the sedative midazolam, which has been used in problematic executions in Arizona, Ohio and Oklahoma.

The case will be argued in April and decided by late June.

Left open by the court's order is whether Oklahoma can carry out an execution that does not involve midazolam.