Atmore, Alabama - A 64-year-old man convicted of the murder of a delivery van driver during a 1998 robbery was executed in Alabama on Thursday, the state Department of Corrections said in a statement.

Keith Edmund Gavin was put to death by lethal injection at a prison in Atmore for the shooting of William Clayton, a 68-year-old father of seven.

Gavin "was pronounced deceased by a physician at 6:32 pm," said the statement, adding that he had received four visitors before being put to death.

There have been 10 executions in the US this year.

Clayton was killed in the town of Centre while withdrawing money from an ATM to take his wife out to dinner, according to court documents.

Gavin, who maintained his innocence throughout court proceedings, was on parole at the time after serving nearly 17 years in prison for a previous murder in Illinois.

Gavin's was the third execution in Alabama this year, with the state also carrying out the first-ever US execution using nitrogen gas.

The Supreme Court granted a temporary halt earlier this week to the planned execution in Texas of another man.

Ruben Gutierrez (47) was sentenced to death for taking part in the 1998 killing of Escolastica Harrison, an elderly manager of a mobile home park in the city of Brownsville, which borders Mexico.

His lawyers have argued that there was no physical evidence of Gutierrez's presence at the scene, and that he confessed when police threatened to arrest his wife and place his children in foster care.

After his appeals were rejected in lower courts, Gutierrez appealed to the Supreme Court, which granted a temporary stay on Tuesday while it considers whether to take up the case.

The death penalty has been abolished in 23 US states, while six others (Arizona, California, Ohio, Oregon, Pennsylvania, and Tennessee) have moratoriums in place.