Hundreds of Indonesian Islamists rallied in central Jakarta to demand the stoning to death and public caning of celebrities who allegedly appear in homemade sex videos circulating online.
About 1,000 protesters led by radical group Hizbut Tahrir shouted "Allahu akbar" (God is greater) and brandished black flags and banners with slogans such as "Arrest those who commit promiscuous sex".
The protest came hours after the rock star suspected of making the videos of himself having sex with two celebrity girlfriends surrendered to police.
Hizbut Tahrir spokesman Mohammed Ismail Yusanto said the Internet was a threat to Islamic values in the world's most populous Muslim-majority country.
He said Islamic or sharia law should be applied across the archipelago of some 240 million people, including the stoning to death of adulterers.
"The widespread circulation of the celebrity sex videos shows the bad side of uncontrolled information technology, which will surely become one of the most terrible destroyers of morality," he said in a statement.
"Based on sharia law... those who are married should be stoned to death and the unmarried should be caned 100 times in public.
"With that kind of punishment it is guaranteed promiscuous sex won't spread wildly like it is now."
Radical groups like Hizbut Tahrir have little popular support in Indonesia, which is constitutionally secular and culturally moderate.
But sharia bylaws are in place in many local jurisdictions and Islamist vigilante groups have repeatedly attacked minorities and liberals, often under the noses of police.
President Susilo Bambang Yudhoyono has backed calls for tighter controls on the Internet in response to the sex video furore. Last week he warned that the nation risked being "crushed" by the information technology "frenzy".
Singer Nazril Ariel, 28, surrendered to police early Tuesday and faces charges relating to the videos, which appear to show him having sex with television celebrities Luna Maya, 26, and Cut Tari, 32.
The celebrities deny uploading the clips but could still face up to 12 years in jail under a controversial 2008 anti-pornography law.
Tari is married and also could face up to nine months in prison for adultery.
Hizbut Tahrir Indonesia coordinator Fadilah Karimah, 32, said she would like to see adulterers buried up to their necks in public places and pelted with stones until dead.
"Those people who have sex before marriage should be caned with a stick 100 times in public. Adulterers should be half-buried and stoned to death," she told AFP at the rally.
"This is appropriate punishment as what they did was dirty, shameful and despicable. They should be prepared for such a punishment if they want to earn a place in heaven.
"The more people who see it the better."