Iran on Wednesday hanged a woman convicted of murdering her husband, whom she married while still a child, defying an international campaign for clemency, rights groups said.

Samira Sabzian, who had been in prison for the past decade, was executed at dawn in Ghezel Hesar prison in the Tehran satellite city of Karaj, the Norway-based Iran Human Rights (IHR) group said.

Her execution comes as concern grows over the number of people executed this year by Iran, where hundreds of people have been hanged mainly on murder and drug charges, including more than a dozen women.

IHR said Sabzian was a child bride who had married her husband at the age of 15 and had been a victim of domestic violence, according to relatives.

The Hengaw rights group also confirmed the execution of the woman, now believed to be in her late 20s or early 30s, saying that she was originally from the city of Khorramabad in the western Lorestan province.

Amnesty International said it was horrified by the reports of the "chilling execution," saying the mother of two was "subjected to a forced and early marriage as a child."

The office of the U.N. High Commissioner on Human Rights said it was alarmed by the execution, saying Sabzian had been forced to marry her husband at age 15.

"We again urge Iran to establish a moratorium on all executions with a view to abolishing death penalty," it added.