Two separate court rulings on Wednesday night temporarily blocked a series of executions scheduled to take place over an 11-day period in the US state of Arkansas.

The scheduled executions, comprising eight in total, marked the most by a state in such a compressed period since the US Supreme Court reinstated the death penalty in the 1970s.

However, a district judge ordered a temporary restraining order against the use of the drug vecuronium bromide in the executions after McKesson Corporation filed an appeal saying its drugs were falsely acquired.

Vecuronium bromide is often used in executions in the US as a paralyzing agent that stops the inmate from breathing. It was used in a "botched" Oklahoma execution in 2014, when a conscious inmate faced 40 minutes of paralysis and agonizing pain before suffering a heart attack.

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Earlier this week, McKesson said it refunded the Arkansas Department of Correction (ADC) for the drug after it agreed to return the supplies. But the ADC has failed to do, according to the drug supplier.

According to court documents, the ADC acquired the drug under false pretense, telling McKesson that it would strictly be used for medical purposes. McKesson argued that its use in lethal injections is prohibited under its "supplied agreement," adding that the corrections officer did not say it would be used in executions.

"We are pleased that the court has ruled in our favor and we look forward to the return of our product," McKesson said in a statement on Wednesday.

'Temporary relief'

In a separate ruling, the Arkansas Supreme Court voted 4 to 3 to grant a stay of execution for Stacey Johnson, an inmate who had been scheduled for execution on Thursday.

Johnson has claimed that advanced DNA testing will prove he did not commit the murder of a 25-year-old mother of two in 1993.

Arkansas Governor Asa Hutchinson said he was disappointed by the latest setback to the execution schedule.

"When I set the dates, I knew there could be delays in one or more of the cases, but I expected the courts to allow the juries' sentences to be carried out since each case had been reviewed multiple times by the Arkansas Supreme Court, which affirmed the guilt of each," he said.

Human rights campaigners and anti-death penalty activists have warned that the latest rulings do not mark an end to the "deadly spate of executions."

"While this ruling once against brings temporary relief, Arkansas continues to show no regard for human rights by rushing prisoners to their deaths," said Amnesty International's James Clark in a statement.

ls/sms (AP, Reuters, dpa)