ST. LOUIS (AP) — Missouri Gov. Jay Nixon on Friday halted the execution of convicted killer Allen Nicklasson, citing concerns about the use of propofol as an execution drug.

Nixon also ordered the Missouri Department of Corrections to come up with a different way to perform lethal injections that does not include the popular anesthetic.

"As governor, my interest is in making sure justice is served and public health is protected," Nixon said in a statement. "That is why, in light of the issues that have been raised surrounding the use of propofol in executions, I have directed the Department of Corrections that the execution of Allen Nicklasson, as set for October 23, will not proceed."

Nixon said Missouri Attorney General Chris Koster will immediately ask the Missouri Supreme Court to set a new execution date for Nicklasson.

The execution was scheduled to be the first in the country using propofol.

Propofol is the leading anesthetic used in America's hospitals and clinics and nearly 90 percent of the nation's propofol comes from Europe. The European Union has threatened to limit the export of propofol if it is used in an execution.

The leading propofol maker, Germany-based Fresenius Kabi, and anesthesiologists had warned of a possible propofol shortage that could impact millions of Americans. Messages seeking comment from Fresenius Kabi were not immediately returned.

Drug makers in recent years have stopped selling potentially lethal pharmaceuticals to prisons and corrections departments because they don't want them used in executions. That has left the nearly three dozen death penalty states, including Missouri, scrambling for alternatives.

Missouri altered its execution protocol in April 2012 to use propofol. The drug gained some level of infamy in 2009 when pop star Michael Jackson died of a propofol overdose.

Messages left with a spokesman for the Missouri Department of Corrections and with the office of Attorney General Chris Koster, who requested the execution date for Nicklasson, were not immediately returned.

Nixon's decision also leaves uncertain the execution scheduled for Nov. 20 for another convicted killer, Joseph Franklin.