The Saudi Interior Ministry acknowledged that Amina bint Abdul Halim bin Salem Nasser was executed Monday in the northern province of al-Jawf. Amnesty International said it believed she was beheaded on charges of practicing witchcraft and sorcery.
Philip Luther, interim director for Middle East affairs at Amnesty International, said the details surrounding the crime and execution weren't known in detail. Authorities in Saudi Arabia, however, often use sorcery as a reason to punish people for exercising rights to free speech or religion.
"The charges of 'witchcraft and sorcery' are not defined as crimes in Saudi Arabia and to use them to subject someone to the cruel and extreme penalty of execution is truly appalling," he said in a statement.
Amnesty International said at least 79 people were executed in Saudi Arabia this year, up from the 27 reported in 2010. The Sunni kingdom imposes the death penalty for crimes ranging from adultery to murder.
Earlier this month, Amnesty International published a 71-page report detailing a "new wave of repression" in the Saudi kingdom since the start of the Arab Spring this year.
Amnesty International says the crackdown is related to a "secret draft anti-terror law" in Saudi Arabia that equates peaceful dissent to terrorism. The rights group accused the Sunni monarchy of detaining "thousands of people" without charge, adding torture of detainees is "rife" in the country.