Troy Davis, 42, who sat on death row for 20 years after being found guilty of killing police officer Mark MacPhail in 1989, was executed by lethal injection. His death came despite new information that defense lawyers said could have saved his life.

Since the conclusion of his trial two decades ago, seven of nine witnesses recanted or changed their testimony, some even alleging police intimidation. Critics voiced skepticism over the verdict, arguing that the prosecutors had very little physical evidence to incriminate the defendant.

Meanwhile, a steady stream of petitions poured in from around the world requesting a stay of execution, including from Pope Benedict XVI and former US President Jimmy Carter. Even a former US prosecutor, Bob Barr, argued for a stay of execution.

On the same day that Troy Davis was executed, Iran publicly hanged a 17-year old boy convicted of killing a popular athlete, while China executed a Pakistani national convicted of drug smuggling.

“This is a bleak day for human rights worldwide,” said Guadalupe Marengo, Amnesty International’s Deputy Director for the Americas. “By executing these individuals, these countries are moving away from the global trend to abolish the death penalty.”

Russia, as a member of the Council of Europe, declared a moratorium on capital punishment and has not executed anyone since 1996.

Meanwhile, Europeans have expressed their dismay with the execution, some calling it "barbaric."

“The United States are a very democratic country, but these are barbaric practices,” commented Laurent Fabius, a prominent Socialist lawmaker and former French prime minister, speaking on Europe 1 radio.

Robert Badinter, who as justice minister supervised the abolition of the death penalty in France in 1981, called the execution a “defeat for humanity.”

“This affair will remain as a stain on the justice system of the United States,” he said.

For RT commentary on this story, click here.