Story highlights Catherine Ashton demands Iran impose a moratorium on the death penalty

She calls on Iran to halt the pending execution of a woman and a pastor

Sakineh Mohammadi Ashtiani has been sentenced to die by stoning

Pastor Youcef Nadarkhani has been sentenced to die by hanging

The Europe Union foreign policy chief Catherine Ashton demanded Friday that Iran halt the pending executions of a woman sentenced to die by stoning and a Christian pastor convicted of apostasy.

Ashton also called on Iran to impose an immediate moratorium on the death penalty, saying the country leads the world in the number of executions per inhabitant.

"Thousands of individuals remain at risk of execution, including Ms Sakineh Mohammadi Ashtiani and Pastor Youcef Nadarkhani. The EU reiterates its call on Iran not to execute them," Ashton said in a written statement.

"Hundreds of individuals were executed in 2011 after grossly unfair trials, without the right of appeal and for offenses, which according to international standards should not result in capital punishment."

Ashtiani's case drew international attention after she was sentenced to die by stoning for adultery.

Iranian officials later said she would be executed, though the method of execution -- stoning vs. hanging -- was still being debated.

Ashtiani, a mother of two, will be executed as soon as a decision is reached, Iranian officials have said.

Ashtiani was convicted of adultery in 2006 and was later convicted of being an accessory to murder in her husband's death. Her family has denied that she played any role in the death.

Human rights groups and various governments have urged Iran not to execute Ashtiani. Last year, Ashton demanded that Iran stop the execution from proceeding, and British Foreign Minister William Hague called the proposed stoning a "barbaric punishment."

International pressure also has been mounting over the case of Nadarkhani, who was sentenced to death by hanging after being convicted of apostasy in 2011.

Nadarkhani is the leader of a network of Iranian house churches and was first charged with apostasy in 2010 for converting from Islam to Christianity.

An Iranian court found Nadarkhani has Islamic ancestry and, therefore, had to recant his faith. Nadarkhani was convicted and sentenced to die after refusing to recant his faith.