Utah's decision to reintroduce the firing squad as an execution method if lethal injections drugs are unavailable bucks an international trend.
Utah and Oklahoma are the only states which allow for the firing squads. However, Oklahoma would allow them only as a last resort, if all other methods are ruled unconstitutional. The U.S. is the only country in the Americas to allow the use of firing squads in civilian cases besides Cuba.
Many countries that use firing squads usually reserve them for military cases or during war time. An exception is Indonesia which is preparing to execute 10 drug smugglers, nine of them foreigners, by firing squad after judicial reviews are complete.
China, where thousands of people are believed to be executed each year, traditionally used firing squads. But in recent years China has begun using lethal injections and that is now believed to be the main technique. The exact number of executions in China is a state secret, but it is thought to be the most in the world.
Firing squads remain the preferred method of execution in Somalia and Equatorial Guinea and are known to have been used in Iran, Iraq and Saudi Arabia. North Korea is believed to use them.
According to Amnesty International at least 778 executions, excluding China's, were carried out around the globe in 2013 — the last year for which numbers were available — compared to 682 in 2012. The organization did not provide a breakdown of executions methods.
At least 1,927 people were known to have been sentenced to death in 57 countries in 2013, up from 1,722 death sentences in 58 countries in 2012, according to Amnesty.
Videos smuggled out of North Korea reportedly show public executions by firing squad. South Korea's spy agency believes North Korea used a firing squad last year to execute several people close to leader Kim Jong Un's uncle, Jang Song Thaek, who was considered the country's second most powerful person before his sudden purge and execution in December 2013.
Vietnam, with nearly 700 people on death row, switched from firing squads to lethal injection on humanitarian grounds in 2011. Since then it has only executed a handful of people because of the difficulty in acquiring the required drugs.
Taiwan's death row total stands at more than 100. The number of executions, carried out by handgun shooting either to the heart or to the brain, declined after 2000 due to public opposition, with none between 2006 and 2009. They resumed in 2010 following a change in president and renewed sentiment in favor of the policy.
Thailand executed prisoners by a machine gun or automatic rifle fired by an executioner until 2002, when the method was changed to lethal injection. There have been no executions since 2009.
In Iran, Saudi Arabia and Iraq, three countries that have some of the highest execution rates in the world, firing squads are rarely used.
In Saudi Arabia, the usual method of execution is beheading by a swordsman. In 2013, a firing squad was used in the execution of seven men convicted of looting and armed robbery. Press reports at the time suggested it was because a swordsman was not available.
During Iran's 1979 revolution, the Islamic clerical regime that came to power used firing squads to execute some senior military officers from the regime of the ousted shah. But the method is rarely used now, and the vast majority of executions are by hanging.
Hanging is also the method most commonly used in Iraq, although there have been cases where firing squads have been employed.
The United Arab Emirates uses firing squads for all executions, but death penalty sentences are rarely carried out. The most recently reported execution was in January 2014.
Capital punishment has been completely abolished across Europe with the former Soviet nation of Belarus being the sole exception.
Abolition of the death penalty is a pre-condition for entry into the European Union. The EU's Baltic Sea member Latvia was the last country to retain capital punishment for murder, but only during wartime. It was abolished in 2012.
The exact number of people executed in Belarus is believed to be three in 2014, according to human rights' groups, but there is some uncertainty about that figure because of the general lack of transparency there. It is believed to have been below 10 executions in the past decade. Execution is done by shooting in the back of the head, but the death penalty's use is shrouded in secrecy.
Somalia and Sudan routinely execute the most people in this region. In 2013, Somalia executed 34 people while Sudan put 21 to death, according to Amnesty International. Somalia generally uses firing squads to carry out its death sentences; two soldiers were executed by shooting on Tuesday, according to the country's military court.
The death penalty is legal in more than a dozen other countries in the region, although only five carried out executions in 2013. In recent years, the only other country in the region to use firing squads was Equatorial Guinea, which shot four people last year but then issued a moratorium on future executions, Amnesty said.
LATIN AMERICA AND THE CARIBBEAN
In general, the death penalty has been abolished across the region, if not by law in each country, then on a de facto basis, according to the World Coalition Against the Death Penalty. The last known execution in the region was in Cuba in 2003 by firing squad.
Associated Press Writers Michael Astor in New York, David Thurber in Bangkok, Jan Olsen in Copenhagen, Lee Keith in Cairo, Sarah DiLorenzo in Paris and Peter Prengamen in Buenos Aires contributed to this report.