HUNTSVILLE, Texas (AP) - Texas' prison agency is scrambling to find a supplier to replenish its inventory of execution drugs, which will be used up if the state goes forward with two lethal injections scheduled for this week and next.

Prison officials only have enough pentobarbital for the scheduled executions of Manuel Vasquez on Wednesday and Randall Mays on March 18, but they don't know how they will conduct lethal injections on four others scheduled for April.

The Texas Department of Criminal Justice declined to say why it has not been able to obtain more pentobarbital from the same compounding pharmacy that provided the current batch of the powerful sedative last March. The state switched to that source several months after its previous supplier cut ties, citing hate mail and potential litigation after its name became public through an open records request from The Associated Press.

Prison officials have since waged a legal battle to keep the name of its latest supplier secret, but it's unclear how much longer they can do so after a state judge last year ordered the agency to divulge the source.