ST. LOUIS — With drugs needed for lethal injection in short supply and courts wrangling over how to execute prisoners without them, Missouri’s attorney general is floating one possible solution: Bring back the gas chamber.

In court filings and interviews this week, Attorney General Chris Koster noted that Missouri statutes allow two options for executions: lethal injection and death by gas. Koster’s comments come amid his growing frustration over the Missouri Supreme Court’s refusal to set execution dates until lethal injection issues are resolved.

“The Missouri death penalty statute has been, in my opinion, unnecessarily entangled in the courts for over a decade,” Koster said Wednesday in an email exchange with The Associated Press.

Asked about concerns by some who say using lethal gas could violate condemned inmates’ constitutional guarantee against cruel and unusual punishment, Koster responded: “The premeditated murder of an innocent Missourian is cruel and unusual punishment. The lawful implementation of the death penalty, following a fair and reasoned jury trial, is not.”

Missouri used gas to execute 38 men and one woman from 1938 to 1965. After a 24-year hiatus, the death penalty resumed in 1989. Since then, 68 men — all convicted murderers — have been executed in the state, all by lethal injection. But as concerns were raised in the courts about the lethal injection process, Missouri has carried out just two executions since 2005.

A return to lethal gas would create an expense because Missouri no longer has a gas chamber. Previous executions by gas took place at the Missouri State Penitentiary in Jefferson City. Prisoners were moved out of that prison a decade ago and it is now a tourist attraction — complete with tours of what used to be the gas chamber.

Like other states with the death penalty, Missouri for years used a three-drug mixture to execute inmates. But those drugs are no longer being made available for executions, leaving states to scramble for solutions.

Last year, Missouri announced plans to use propofol, the anesthetic blamed for pop star Michael Jackson’s 2009 death — even though the drug hasn’t been used to execute prisoners in the U.S. and its potential for lethal injection is under scrutiny by the courts.

A 2012 lawsuit filed in U.S. District Court in Kansas City on behalf of 21 Missouri death row inmates claimed the use of propofol would be cruel and unusual punishment.

In an interview last week, Missouri Supreme Court Chief Justice Mary Russell said the court is “waiting for resolution” from the U.S. District Court.

Koster on Monday asked the Missouri Supreme Court to set execution dates for two long-serving inmates, arguing that time is running short to use a limited, nearly expired supply of propofol.

Richard Dieter, executive director of the Death Penalty Information Center in Washington, said a few other proposals have been made for states to use the gas chamber or the electric chair, but they’ve gone nowhere.

“It’s unlikely that states would go back to these older methods, and if they did I’m not sure they would be upheld” in the courts, he said.

Rita Linhardt, chairwoman of the board for Missourians for Alternatives to the Death Penalty, questioned the practicality of the gas chamber.

“The gas chamber has been dismantled in Missouri, so from a practical point of view I don’t know how that could be done,” Linhardt said. “I would think that would be a considerable cost and expense for the state to rebuild the machinery of death.”