The legal team for the US state of Arkansas has pledged to reverse the legal challenges which stopped them from beginning a series of executions this week.

Court orders have stopped Arkansas from executing eight men by lethal injection in 11 days, ruling that one of the drugs used could result in the killings being cruel and unusual punishment.

The southern state's stock of midazolam – one of the drugs used in the executions – is due to expire at the end of April, hence the rush to carry out an unprecedented number of lethal injections in a short amount of time.

Arkansas' state attorney general Leslie Rutledge has appealed against the court decision saying: "We do have a number of pieces of litigation that we are working (on).

"Attorneys are working around the clock and committed to upholding and defending the rule of law, seeing these executions carried out, seeing justice for the families of those victims."

Bruce Earl Ward and Don William Davis Jr. had been slated to die Monday (17 April) night, the first of four double executions for an 11-day period. A federal judge issued stays for each of the inmates Saturday, according to AP.

On Friday, Pulaski County Circuit Judge Wendell Griffen stopped the state from using its supply of vecuronium bromide after a distributor alleged that prison officials used false pretences to obtain it.

Protests against the lethal injections have garnered support from celebrities such as Johnny Depp. The actor joined an anti-death penalty rally in Little Rock, Arksansas, on 14 April, walking beside Damien Echols, who he campaigned to free, having spent 18 years on death row before being freed.

Depp was asked what he would say to Asa Hutchinson, the Arkansas governor. "I can't, I don't, you know – how do you sleep, man? I don't know. How do you sleep?" he said.

Maya Foa, director of the anti-death penalty campaigners Reprieve, told Sky News: "The drugs slated for use in lethal injection cocktails across the US are simply medicines, designed to save and improve lives and (the) health of patients and (are) being misused in a lethal fashion.

"So it is no surprise that the healthcare industry doesn't want to see medicines used in terrible executions."

John C. Williams, Assistant Federal Public Defender and attorney for some of the death row prisoners stated: "The unnecessarily compressed execution schedule using the risky drug midazolam denies prisoners their right to be free from the risk of torture.

"We are calling on state officials to accept the federal court's decision, cancel the frantic execution schedule, and propose a legal and humane method to carry out its executions."