The U.S. Supreme Court blocked the first scheduled execution of a Texas death row inmate using a new drug cocktail on Tuesday, although the proposed lethal mix was not mentioned in the court's decision to reconsider the merits of the condemned man's appeal.

Cleve Foster was to have been executed hours later for the 2002 slaying of a Sudanese woman in Fort Worth — the first Texas execution since the state switched to pentobarbital in its three-drug mixture. The sedative has already been used for executions in Oklahoma and Ohio.

On Tuesday morning, the high court agreed to reconsider its January order denying Foster's appeal that raised claims of innocence and poor legal help during his trial and early stages of his appeals.

Foster's lawyers also have argued that Texas prison officials violated administrative procedures last month when they announced the switch to pentobarbital from sodium thiopental, which is in short supply nationwide. Foster's lawyers contend that the rules change in Texas required more time for public comment and review. Lower courts have rejected their appeals and attorneys had planned to take their case to the Texas Supreme Court.