Arkansas executed a fourth inmate in eight days, and The Associated Press checked into executions during the same period in other countries where the death penalty is regularly carried out.
Experts cautioned that international statistics on executions are difficult to obtain because many countries shroud the process in secrecy.
"I feel quite certain there are more executions that we don't know about," said Delphine Lourtau, executive director of the Cornell Center on the Death Penalty Worldwide, which maintains a database on executions across the globe.
Lourtau said some of the countries where executions may have taken place but have not been confirmed include Iraq, North Korea, Sudan, Syria, Vietnam and Yemen.
Here's a look at executions carried out in the past week outside the U.S.:
Iran has reportedly executed 10 people since April 20, when Arkansas executed its first inmate since 2005.
Iranian news media reported that 29-year-old Mehdi Mirzaei was executed on April 22 after serving three years in western Iranian city of Khoramabad. He had been sentenced to death for carrying and possession of seven kilograms of amphetamine.
A second person executed the same day was identified by local media as a 21-year-old man sentenced to death for killing another man during an argument about a year and a half ago. He was executed in the northern Iranian city of Babol.
Eight prisoners were hanged in Iran on April 20, according to the Human Rights Activists News Agency, a group run by Iranian human rights activists living outside the Middle Eastern country who collect information from reporters operating in Iran. The agency said the prisoners received death sentences following murder convictions in recent years. No names were given and there was no corroboration by officials, who do not always release details of those executed.
Executions in Iran are typically carried out early in the morning in prison gallows, often with a chair or bench kicked out from under the inmate. Most happen in the presence of families of victims and the condemned.
Public hangings occasionally occur, with the condemned prisoner hoisted up by a crane attached to a rope and noose.
Once a death sentence is imposed in murder cases, the victim's family can halt the execution in lieu of prison time — often through payments to the victim's family.
Citing media reports, the Cornell Center on the Death Penalty Worldwide said a man previously convicted of drug offenses was hanged in Singapore on April 21. The man's name, age and hometown weren't provided.
Three people have been executed since April 20 in Saudi Arabia, all of whom were Saudi men convicted of murder.
One man was executed on April 20 after being found guilty of killing a man with a blow to the head. Three days later, a man convicted of shooting and killing another Saudi was executed. The third execution, on April 24, was of a man convicted of sexually assaulting and murdering a minor.
The kingdom did not say how the executions were carried out. Most executions in Saudi Arabia are done by a sword-wielding executioner who swiftly beheads the prisoner. Some are carried out in public, as a warning to others.
An execution scheduled for April 27 was called off after so-called blood money was paid to the victim's family. The case stemmed from 2009, when a Saudi man fatally stabbed another person in a bout of road rage in the eastern region of Qatif.
Saudi Arabia's legal system allows victims' families in some cases to forgive the convicted murderer or demand compensation in lieu of execution.
China is widely believed to execute more people annually than all other countries combined. Dui Hua, a monitoring group with offices in Hong Kong and San Francisco that uses official government data and unofficial reports on China's criminal justice system, estimates about 2,000 were put to death last year.
The precise figure remains a state secret. Death sentences sometimes get reported, but news on actual executions is rare unless cases are especially high-profile or involve foreigners. Executions traditionally have been carried out by firing squad, although the government began introducing lethal injection several years ago.
Despite its reputation, China's execution rate has dramatically decreased from years past. An estimated 24,000 executions were carried out in 1983, after provincial courts were given powers to mete out capital punishment. Courts are now ordered to impose the death penalty only for the most heinous crimes, and all are subject to review by the supreme court.
Murphy reported from Oklahoma City.
Associated Press reporters Aya Batrawy in Dubai, United Arab Emirates; Nasser Karimi in Tehran, Iran; and Christopher Bodeen in Beijing contributed to this report.
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