COPENHAGEN: The organization that oversees the Nobel Peace Prize said Friday the 1991 prize awarded to Myanmar's Aung Sang Suu Kyi cannot be revoked.

Olav Njolstad, head of the Norwegian Nobel Institute said in an email to The Associated Press that neither the will of prize founder Alfred Nobel nor the Nobel Foundation's rules provide for the possibility of withdrawing the honor from laureates.

"It is not possible to strip a Nobel Peace Prize laureate of his or her award once bestowed," Njolstad wrote. "None of the prize awarding committees in Stockholm and Oslo has ever considered revoking a prize after it has been awarded."

An online petition signed by more than 386,000 people on Change.org is calling for Suu Kyi to be stripped of her Peace Prize over the persecution of Myanmar's Rohingya Muslim minority.

Suu Kyi received the award for "her non-violent struggle for democracy and human rights" while standing up against military rulers.

She became the country's de facto leader after Myanmar held its first free election in 2012 and she led her party to a landslide victory.

On Thursday, former South African archbishop Desmond Tutu urged her to intervene to stop the persecution of the Rohingya. In an open letter, he told his fellow Nobel Peace Prize winner that it is "incongruous for a symbol of righteousness" to lead a country where violence against the Rohingya is being carried out.

Rohingya have described large-scale violence perpetrated by Myanmar troops and Buddhist mobs ? setting fire to their homes, spraying bullets indiscriminately and ordering them to leave or be killed.

Suu Kyi has dismissed the Rohingya crisis as a misinformation campaign.