UTAH politicians have backed a proposal to re-introduce execution by firing squad to avoid problems with lethal injection drugs, 10 years after banning the practice.

The plan would call for a firing squad if the state cannot obtain the lethal injection drugs 30 days before the scheduled execution.

For years, US states used a three-drug combination to execute inmates, but European manufacturers have refused to sell them to prisons and corrections departments over opposition to the death penalty.

Utah axed firing squads out of concern about media attention but Republican state member Paul Ray said it was the most humane way to execute someone because the person dies instantly.

He said: "If we go hanging, if we go to the guillotine, or we go to the firing squad, electric chair, you're still going to have the same circus atmosphere."