WASHINGTON (AFP) - Oklahoma's top appeals court agreed on Thursday to halt all executions in the south-central US state for six months, after a botched lethal injection last month triggered accusations of torture.

Clayton Lockett's execution, in which the convicted murderer and rapist died 43 minutes after the start of the lethal injection and appeared in significant pain, renewed debate over the death penalty in the United States.

The Oklahoma Court of Criminal Appeals set for November 13 the execution of Charles Warner, who had originally been scheduled to be put to death the same evening as Lockett.

After Lockett's bungled execution, that of Warner, sentenced to death for the rape and murder of his girlfriend's 11-month-old baby, was first delayed until May 13.

The attorney-general's office backed the decision, saying in a filing that "the state will not object to a 180-day stay to allow completion of (Oklahoma Public Safety Department) Commissioner Michael C. Thompson's investigation". However, it called "unwarranted" an indefinite stay, as requested by the state corrections director.

President Barack Obama, who backs the death penalty for heinous crimes, condemned the "deeply troubling" incident on April 29.

He has ordered Attorney-General Eric Holder, who is seeking the death penalty in the Boston Marathon bombings case, to conduct a policy review of how the death penalty is applied in the United States.