Authorities in the US state of Alabama plan to execute a man convicted of murdering his former girlfriend on Thursday, despite his victim's family's opposition to the death penalty.

• Read also: A Japanese man who killed seven people by running into passers-by with a truck, before stabbing random people, was executed

Joe Nathan James, a 49-year-old African-American, is to receive a lethal injection in the evening in a penitentiary in this rural state in the southern United States.

He was condemned to the death penalty for having killed, in 1994, Faith Hall, a young woman of 26 years whom he harassed since the end of a short relationship.

Since Alabama set a date for his execution, his victim's daughters, aged three and six at the time of the tragedy, plead for him to be spared.

"Taking her life won't bring Faith back, it won't allow us to turn the page," Terryln Hall told CBS 42.

"We shouldn't take ourselves for God," added his sister Toni Hall. "'An eye for an eye' is not a good principle of life."

After Governor Kay Ivey refused to intervene, these statements were put forward by Joe Nathan James' lawyer in an urgent appeal to the United States Supreme Court asking it to stay the execution.

The Hall sisters "were too young at the time of the trial for their opinion to be taken into account, but the victims and their families (...) deserve to be heard on the question of the sentence finally imposed on the criminals", has writes James Ransom in his appeal, which raises other procedural issues.

If the High Court does not agree with him, Joe Nathan James will become the eighth convict executed since the beginning of the year in the United States.