Human rights group Amnesty International has condemned the US for continuing to execute people for crimes committed when they were children.
Washington sniper suspect Malvo was 17 when he was arrested
In a new report, the organisation says the US was responsible for 13 of
the 20 known executions worldwide in the last decade for crimes
committed before the offender's 18th birthday.
Five of the US executions took place in the last 18 months.
The death penalty is a matter for
individual US states, some of which permit the execution of people for crimes committed when they were teenagers.
According to the report, the US "is the only country in the world to openly carry out child offender executions within the framework of its ordinary criminal justice
"The execution of child offenders has rightly become abhorrent in
virtually every corner of the world, yet the USA is shamefully ignoring the effective ban on executing child offenders," Amnesty International UK Director Kate Allen said in a statement.
"The USA has recently claimed to be 'the global leader in child
protection', but by imposing death sentences on under-age offenders it
undermines international law and its own credibility."
OTHER STATES THAT HAVE EXECUTED CHILD OFFENDERS IN THE PAST 20 YEARS
Democratic Republic of
Source: Amnesty International
Amnesty called for a ban on such executions to be recognised
as a "peremptory norm" of international law, which would make
them illegal everywhere, regardless of whether a country had
signed up to treaties banning the practice.
The issue of execution of juveniles in the US will be brought back into the spotlight later this year with the trial of Washington sniper suspect Lee Boyd Malvo.
He was 17 when he was arrested and charged with murder for his alleged killing partnership with the other accused man, John Allen Muhammad.
But he will be tried in adult court in Virginia - a state which not only implements the death penalty, but allows it for juveniles tried as adults.
Carrie Cantrell, a spokeswoman for Virginia's attorney general, said allowing courts to decide to try juveniles as adults and face adult sentences including the death penalty was part of a package of reforms brought in with popular support to tackle violent crime.
She told BBC News Online that suspects such as Mr Malvo were considered the same as adults.
"These individuals were aware they were committing these crimes, and were aware they are tried as adults," she said.
"In Virginia, we stand on the side of the victim," she said, adding that the reforms made to the state's juvenile justice system in the 1990s were working and had brought about dramatic decrease in violent crime.