A judge in Arkansas has issued an order halting the execution of seven men in an 11-day period after banning the state from using a lethal injection drug it planned to administer.

Pulaski County Circuit Judge Wendell Griffen ruled the state could not use vecuronium bromide as one of three drugs that were to be used in the executions planned for this month.

Arkansas has not executed anyone since 2005, but was set to carry out at least seven executions in April in a move that prompted fierce opposition from death penalty opponents.

However, the decision of Judge Griffen to block the use of vecuronium bromide has the executions on hold, while the Supreme Court also issued a stay in the execution of one man who was scheduled to be put to death on Monday (17 April).

The decision to prevent the use of the drug as part of a lethal injection cocktail was taken after manufacturers of the drug argued they had not been made aware it would be used for executions.

In a letter seen by The New York Times, a lawyer for drug company McKesson said the state "never disclosed its intended purpose to us for these products. To the contrary, it purchased the products on an account that was opened under the valid medical license of an Arkansas physician, implicitly representing that the products would only be used for a legitimate medical purpose."

Among the companies involved in the case is drug company Pfizer, which said it had asked the state of Arkansas to return its products on several occasions but that it had not done so.

The judge has set a hearing to determine whether the state obtained the drugs improperly, the Associated Press reported, with the case to begin on Tuesday. The ruling has postponed the executions, which were set to begin on Monday.