Update at 2:56 p.m. ET: In its brief ruling, the court gave prosecutors 30 days to respond to the defense petition, after which the Supreme Court will decide if the appeal has merit. Foster's defense team said they are encouraged by the ruling."It's not a common procedural posture," Maurie Levin, a University of Texas law professor and one of Foster's attorneys, said. "We're very happy for the stay and that the Supreme Court will be looking at important issues raised."

Cleve Foster, 47, blames his conviction on lawyers he didn't trust, what he called false testimony from police and prosecutors he contends misled jurors. "To me, they were pretty much pulling stuff out of their hats," he told the AP previously from death row.

Earlier posting: The U.S. Supreme Court has blocked an execution in Texas that was to be the state's first with new drug cocktail.

Cleve Foster was to have been executed this evening for killing a Sudanese woman in Fort Worth in 2002.

It would have been the first Texas execution since the state switched to pentobarbital in its lethal three-drug mixture, the Associated Press reports.

In its ruling today, the high court agreed to reconsider its January order denying the 47-year-old's appeal. That appeal had raised claims of innocence and poor legal help during his trial and early stages of his appeals.

Foster's lawyers also argued that Texas prison officials violated administrative procedures when they announced the switch to pentobarbital from sodium thiopental.

There is a national shortage of sodium thiopental, which has been used already in executions in Oklahoma and Ohio.