Washington, May 6 (RHC)-- The Barack Obama administration has launched a review of execution procedures following last week’s botched killing of a death row prisoner in Oklahoma.

Clayton Lockett died of a heart attack 43 minutes after he was injected with untested chemicals in his groin. Prison officials had called off the execution after Lockett remained conscious and convulsed on the gurney.

In his first public comments on Lockett’s death, President Obama called the botched execution "deeply troubling" and said it raises "difficult and profound questions."

Meanwhile, the U.S. Justice Department said the review will focus strictly on the "federal protocol" for how executions are carried out.