The southern state of Arkansas, rushing to execute several inmates before a lethal drug expires next week, put to death two inmates late Monday, the first double execution in the United States in 17 years.
Arkansas Attorney General Leslie Rutledge said that Jack Jones and Marcel Williams, both sentenced to death in the 1990s, were executed by lethal injection after higher courts rejected their final legal appeals.
Arkansas had planned to put eight convicted murderers to death in 11 days - a record, had it been carried out - but four have won reprieves.
Jones, 52, was executed after the US Supreme Court rejected an 11th-hour request from his attorneys asking justices to reconsider a procedural issue from his trial.
Williams, 46, died hours later after his appeals were exhausted. His lawyers had filed a string of last-minute challenges, which included allegations that Jones suffered unnecessarily because he was executed improperly, and that Williams was so obese that it would be hard to find a proper vein for the lethal injection.
Arkansas Governor Asa Hutchinson has said the accelerated execution timetable was necessary as the state's stock of a sedative used in lethal injections will expire at the end of the month.
Rutledge said in a separate statements that the family and friends of the victims had "seen justice carried out".
The execution process began at 7:06 pm (0006 GMT Tuesday) and Jones was pronounced dead at 7:20 pm, the Arkansas Democrat-Gazette newspaper cited Department of Correction spokesman Solomon Graves as saying.
Jones was calm as he made a rambling final statement while strapped to the gurney, saying he tried to become a better person and apologizing to Lacey, a daughter of Jones's victim, 34-year-old Mary Phillips, the paper said, citing media witnesses in the death chamber.
Three hours later the lethal injection process began on Williams, who according to the newspaper refused to make a final statement. He was pronounced dead at 10:33 pm (0333 GMT).
Last minute appeals had delayed the execution, which had been scheduled for one hour after Jones's execution.
Last week, on Thursday, Ledell Lee was put to death in the state's first execution in more than a decade.
Many of the legal clashes over Arkansas's plan focus on use of the drug midazolam, a sedative meant to render a condemned person unconscious before other drugs induce death.
Critics say it does not always adequately sedate prisoners, potentially causing undue suffering.
And McKesson Medical-Surgical, a distributor for pharmaceutical giant Pfizer, had asked courts to ban the use of a paralytic it sells, vecuronium bromide, in the chemical cocktail used to kill prisoners.
Arkansas has scheduled another execution for April 27.
The last US state to execute two convicts in one night was Texas in August 2000.