WASHINGTON, United States (AFP) — A Mississippi man convicted of rape and murder is to be put to death by lethal injection on Wednesday, the third execution in the United States this week.

Charles Crawford, 59, was sentenced to death for the 1994 rape and murder of Kristy Ray, a 20-year-old college student.

The execution is to be carried out at 6:00 pm Central Time (2300 GMT) at the Mississippi State Penitentiary in Parchman.

Two convicted murderers were put to death on Tuesday — in Florida and Missouri — and another execution is scheduled for Friday.

Richard Djerf, 55, is to be executed by lethal injection in Arizona on Friday for the brutal 1993 murders of four members of a Phoenix family.

There have been 37 executions in the United States so far this year, the most since 2013, when 39 inmates were put to death.

Florida has carried out the most executions with 14, followed by Texas with five and South Carolina and Alabama with four.

Thirty-one of this year’s executions have been carried out by lethal injection, two by firing squad and four by nitrogen hypoxia, which involves pumping nitrogen gas into a face mask, causing the prisoner to suffocate.

The use of nitrogen gas as a method of capital punishment has been denounced by United Nations experts as cruel and inhumane.

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.”