MIAMI, United States (AFP)— A Gulf War veteran convicted of killing his girlfriend and her three young children was executed by lethal injection in the southern US state of Florida on Thursday.

Jeffrey Hutchinson, 62, was put to death for the murders of Renee Flaherty, 32, and her children — Geoffrey, 9, Amanda, 7, and Logan, 4.

Hutchinson’s lawyers claimed he suffered from mental illness as a result of his experiences during the 1990-1991 Gulf War, but appeals to halt his execution were rejected.

He was executed at 8:14 pm local time Thursday (0014 GMT Friday), the Florida Department of Corrections said in a statement.

According to court documents, Hutchinson argued with Flaherty on the evening of September 11, 1998, packed his clothes and guns into his truck, and went to a bar.

He then returned home and fatally shot Flaherty and her children with a 12-gauge shotgun.

Following the murders, Hutchinson called 911 and said, “I just shot my family.”

When sheriff’s deputies arrived, they found Hutchinson dazed on the floor of the garage with blood on his clothes and gunshot residue on his hands.

The phone was still connected to the 911 dispatcher.

Hutchinson claimed at trial that the murders were carried out by two masked and armed intruders who shot Flaherty and the children and then fled.

There have been 15 executions in the United States this year: 11 by lethal injection; two by firing squad; and two using nitrogen gas.

The death penalty has been abolished in 23 of the 50 US states, while three others — California, Oregon and Pennsylvania — have moratoriums in place.

President Donald Trump is a proponent of capital punishment and, on his first day in office, called for an expansion of its use “for the vilest crimes.”