Atmore, Alabama - Two people were executed by lethal injection in the United States on Thursday, one in Alabama and one in Texas.

Casey McWhorter (49) was put to death at a prison in Atmore, Alabama, for the 1993 murder of Edward Williams, who was shot to death during a robbery.

McWhorter had just turned 18 years old at the time of the crime.

His two accomplices, one of whom was the son of the murdered man, were aged 16 and 15 and were spared the death sentence because they were juveniles.

McWhorter "was pronounced deceased by a physician at 6:56 pm," the Alabama Department of Corrections said in a statement.

David Renteria (53) was executed at the Texas State Penitentiary in the town of Huntsville for the November 2001 murder of a five-year-old girl, Alexandra Flores.

He was convicted of abducting Flores from a Walmart in El Paso, Texas, where she had been Christmas shopping with her parents. Her burned body was found the next day. She had been strangled.

At his trial, Renteria claimed he was forced by gang members to dispose of the girl's body but denied murdering her.

On Thursday in his last statement, Renteria pleaded for forgiveness to the relatives of Flores and others whom he had caused pain.

"There is not a day that goes by that I do not think about that fateful event of that day and what transpired," he said, according to a statement by the Texas Department of Criminal Justice which confirmed the execution.

"I will see you all in the other world," Renteria added. "I'm ready, warden. Send me home."

There have been seven executions in Texas this year and 21 in the United States.

According to a recent Gallup Poll, 53% of Americans support the death penalty for someone convicted of murder, the lowest level since 1972.

Capital punishment has been abolished in 23 US states, while three others – California, Oregon, and Pennsylvania – have observed a moratorium on its use.

Executions have been carried out in five states this year: Alabama, Florida, Missouri, Oklahoma, and Texas.

The death penalty has been primarily carried out by lethal injection in recent years, but Alabama intends to execute a person next year using nitrogen gas.

Alabama Governor Kay Ivey has set January 25 as the execution date for Kenneth Smith (58), who was sentenced to death for a 1988 murder.