Raiford, Florida - Edward James was put to death in Florida by lethal injection on Thursday, marking the fourth execution in the US this week.

The Florida Department of Corrections announced that James (63) was executed at 8:15 PM Thursday at the Florida State Prison in Raiford, outside Jacksonville in the north of the state.

James had been convicted in the 1993 rape and murder of an eight-year-old girl, Toni Neuner, and the murder of her grandmother, Betty Dick (58).

His was the fourth execution this week, following that of Wendell Grissom (56) in Oklahoma on Thursday.

Justice Aaron Gunches executed by lethal injection in Arizona

Grissom was sentenced to death for the 2005 murder of Amber Matthews (23), who was shot in the head while trying to protect a friend's two young daughters.

He was pronounced dead 10 minutes after the execution process began at the state penitentiary in McAlester, the Oklahoma Department of Corrections said in a statement.

The department said the execution was carried out using a three-drug protocol: Midazolam, which causes sedation, Vecuronium Bromide, which halts respiration, and Potassium Chloride, which stops the heart.

On Tuesday, Jessie Hoffman (46) was put to death by nitrogen gas in Louisiana.

Hoffman, who was convicted of the 1996 rape and murder of Molly Elliott, a 28-year-old advertising executive, was the first person executed in Louisiana in 15 years.

Only one other state, Alabama, has carried out executions by nitrogen hypoxia, which involves pumping nitrogen gas into a facemask, causing the prisoner to suffocate. The method has been denounced by UN experts as cruel and inhumane.

Murder Two men convicted in plot to kill Iranian-American journalist

Aaron Gunches (53), who was sentenced to death for the 2002 murder of Ted Price, his girlfriend's ex-husband, was executed in Arizona on Wednesday.

Gunches had abandoned legal efforts to halt his execution.

The vast majority of US executions since the Supreme Court reinstated the death penalty in 1976 have been performed using lethal injection, although South Carolina executed a man by firing squad on March 7.

There have already been ten executions in the US this year, following 25 last year.

The death penalty has been abolished in 23 of the 50 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."