Troy Davis, an African-American man sentenced to death for the 1989 murder of a white police officer, was executed by lethal injection in Georgia despite several last-minute appeals by his defense team, doubts about his guilt and numerous pleas for clemency.

Originally scheduled for 7:00 p.m. Wednesday, the execution was finally carried out shortly after 11:00 p.m. after the U.S. Supreme Court rejected an appeal by Davis' attorneys, a spokesman for the Georgia Diagnostic and Classification Prison in the town of Jackson told reporters.

"The incident that night was not my fault. I did not have a gun. I am innocent," Davis said moments before receiving the lethal injection, several witnesses told reporters.

Hundreds of people held a vigil Wednesday outside the prison while awaiting the Supreme Court's ruling on the death-row inmate, who was convicted and sentenced to death in 1991 for the Aug. 19, 1989, murder of policeman Mark MacPhail in a Burger King parking lot in Savannah, Georgia.

MacPhail had gone to the aid of a homeless man who was being beaten.

Davis' case, which his defense team presented as the prototype of a black man wrongly convicted for killing a white man, has reopened debate over the death penalty in the United States.

Pope Benedict XVI and former U.S. President Jimmy Carter were among the prominent advocates calling for Davis' death sentence to be commuted, while a million people around the world had signed an online petition to save the man's life.

Seven of the nine eyewitnesses who had testified in court against Davis later retracted all or part of their statements, defense attorneys said.

Prosecutors, however, argued in court that Davis first shot and wounded a man in the face earlier that same day and later shot and killed MacPhail and said that ballistics evidence showed a clear connection between the two crimes.

The slain police officer's mother, Anneliese MacPhail, told reporters Wednesday that she was certain of Davis' guilt.