A death row inmate scheduled to be executed in an Arkansas prison on Thursday was granted a stay by the highest court in the US state hours before his lethal injection, his attorneys said.

Stacey Johnson is the fourth prisoner in Arkansas to receive a reprieve from execution this month, frustrating state authorities' efforts to run a batch through capital punishment before a key drug in the lethal injections expires.

The stay for Johnson stemmed from a bid to have an evidentiary hearing related to his request for DNA testing to prove his innocence.

"We are grateful and relieved" at the ruling by the Arkansas Supreme Court regarding Stacey Johnson," said Innocence Project senior staff attorney Nina Morrison, whose group is defending Johnson.

She argued that a fellow death row inmate Ledell Lee -- also scheduled to die Thursday -- deserved the same right to a hearing.

"As we argued in our brief, there is a significant amount of DNA evidence that has never been tested which could exonerate Mr. Lee and identify the real perpetrator of the crime."

Arkansas' Governor Asa Hutchinson, a Republican, had planned for eight men on death row to be executed within an 11-day period before the end of April, when the state's stock of midazolam, a sedative used in the lethal injections, expires.

But amid public opposition to the death penalty -- including protests in the state capital Little Rock including actor Johnny Depp and a judge linked to one of the cases -- lawyers obtained stays for three other executions.

Jason McGehee, who was to be put to death on April 27, received a month-long stay two weeks ago because of a parole board's clemency recommendation.

Then, last Friday, Arkansas' Supreme Court suspended, with no explanation, the execution of prisoner Bruce Ward planned for Monday this week.

And late on Monday, after inmate Don Davis ate what was supposed to be his "last meal" and just minutes before his execution, the US Supreme Court gave a last-minute ruling sparing him.

But Arkansas' attorney general, Leslie Rutledge, has pledged to overcome the stays and haul Ward and Davis back into the death chamber.

Last week, Johnson's lawyer lodged a request for a DNA test to verify whether his client's protestations of innocence were founded. Johnson, a black man, was sentenced for the 1993 murder of a white woman.

Lee, who is also black, was sentenced to death in 1993 for the murder of his neighbor, a white woman.

source: AFP