The state of Ohio executed a man who killed a security guard while robbing a bookstore amid a drug-fueled crime spree, officials said Wednesday.

Frederick Treesh, who was stealing money to buy more cocaine at the time of the 1994 murder, is the fourth inmate executed so far this year in the United States.

His death by lethal injection was declared at 10:37 am (1537 GMT), a spokesman for the state's prison department told AFP.

He expressed remorse in his last words, telling observers that he wished a photo of his execution could be used to convince others to stay away from drugs.

"This is where drugs lead you. This is true life," Treesh said.

"I am here for Henry Dupree. I'd like to apologize to the family for what I've done. I'm sorry."

Treesh also thanked prison staff and his execution team, saying "they treated me well."

Treesh, 48, had exhausted his appeals after 18 years on death row and was denied relief by Republican Governor John Kasich, who had previously commuted the sentences of four other death row inmates and expressed reservations about the death penalty.

Treesh was condemned to die for the murder of a 58-year-old security guard and the attempted murder of a 42-year-old salesman in the armed robbery at a bookstore in Eastlake, Ohio. He was arrested after a lengthy high speed chase.

The crime capped a three-week spree of violence and sexual assault in five other states (Michigan, Indiana, Iowa, Minnesota and Wisconsin) committed with an accomplice as they sought money to buy more drugs, court documents showed.

Treesh had previously expressed remorse while in prison and said the murder was not premeditated.

"I am living proof of what drugs can do to you. If it saves one kid, then maybe my dying is not in vain, this is the only positive thing I can do to try and help right a wrong," he told the local paper.

Treesh is the 50th person executed in Ohio and the 1,324th in the United States since the death penalty was reinstated in 1976, according to the Death Penalty Information Center.

There are currently more than 3,000 people on death row in the United States.