A federal appeals court has rejected an appeal by four Oklahoma inmates to stay their executions scheduled over the next three months, including a planned lethal injection next week that has drawn international attention.

The 10th U.S. Circuit Court of Appeals on Friday denied the request to intervene by inmates Julius Jones, Wade Lay, Donald Grant and Gilbert Postelle.

Jen Moreno, an attorney for the four death row inmates, called the ruling “inexplicable.”

“We’re kind of in the process of figuring out what’s next,” Moreno told The Associated Press on Saturday. “Our team is spending this weekend looking over the ruling.”

The court ruled that a federal judge was not wrong in finding that the four were unlikely to succeed on the merits of their claims, including their argument that the use of the sedative midazolam during the execution would likely cause severe pain.

The court also turned aside a claim that requiring the four to select an alternative method of execution would violate their religious beliefs by effectively causing them to assist in their own suicide.

“Appellants are not paying for their religious beliefs with their lives; at most they are forfeiting a delay in execution of a sentence that ... is constitutional,” the court ruling stated.

The four also had argued that a 2011 change in state law violated a constitutional ban on ex post facto laws by changing from a lethal dose of a barbiturate combined with a paralyzing drug, to a broad definition of a deadly amount “of a drug or drugs.”

The ban on ex post facto laws, the court said, prohibits increasing the punishment for a crime after the crime was committed, and that it does not apply in the inmates’ cases.