Texas, in the southwestern United States, has carried out its 400th execution since reinstating the death penalty in 1982.
Johnny Ray Conner was put to death by lethal injection Wednesday. The 32-year-old man was condemned in 1999 for the fatal shooting of a convenience store owner in Houston during a robbery.
In his last statement to witnesses, Conner apologized for his actions, but denounced his execution as "unjust." He was the 21st condemned inmate executed in Texas this year. The state leads the U.S. in carrying out the death penalty.
The European Union urged Texas Governor Rick Perry to ban all executions before Conner's death. But a spokesman for the governor said it is a "just and appropriate punishment for the most horrible crimes committed against our citizens."
More than 1,000 condemned inmates have been put to death since the U.S. Supreme Court lifted a moratorium on executions in 1976.