HOUSTON -- A Texas appeals court panel has upheld a lower court's order that the state's prison agency must identify its execution drug supplier.

The ruling Thursday from the 3rd Court of Appeals is in response to a lawsuit and has limited impact. Lawyers seeking to block the executions of two prisoners in early 2014 filed the suit. A state law that keeps the name of the drug provider confidential took effect Sept. 1, 2014.

One of the attorneys who filed the lawsuit, Maurie Levin, says the ruling means the Texas Department of Criminal Justice must disclose who the supplier was at the time the suit was filed. State lawyers argued such a disclosure could expose the supplier to physical harm.

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Prison agency spokesman Jason Clark says the decision will be appealed to the Texas Supreme Court.

Death penalty states have been struggling in recent years to find suppliers for execution drugs after European companies have refused to sell to them. Some states have changed the mix of drugs used while others have tried to import drugs from international pharmacies.

In Texas, the lawsuit was brought by three lawyers representing death row inmates who said they wanted to know that the drugs would not produce an unconstitutional level of pain and suffering, according to the Austin American-Statesman. Prison officials declined to name the source, saying they came from a licensed compounding pharmacy in Texas. Both convicts were executed while the case was pending, according to the Houston Chronicle.