Jakarta – Indonesian officials have warned radical Muslim groups not to attack nightclubs and other businesses deemed sinful in Islam during the Ramadan fasting month, which started yesterday.

Nightclubs, massage parlours and saunas are normally closed for business during Ramadan, Indonesia's Antara news agency reported.

But hardline Islamic organisations, which are not banned in Indonesia, have in recent years attacked those businesses which continued to operate.

Last Thursday, a red-light district in Sumatra was attacked by radical Muslims. Many houses believed to be used for vice activities were set on fire.

Arie Budhiman, who heads the Jakarta tourism and culture office, said: "The Jakarta police chief has made it quite clear that unauthorised mass organisations are not permitted to perform supervisory functions."

Enforcement should be handled by only the police and the city government's security and order agency, and his office, he said.

He advised Muslim groups to report to the authorities any recalcitrant nightspots or other businesses that operate outside the officially permitted hours instead of taking matters into their own hands.

Arie said his office had sent notices to 1,129 bars, clubs, massage parlours, nightclubs and karaoke operators early this month, detailing which of them have to close during the fasting month, Antara reported on Friday.

All nightclubs, massage parlours and saunas are to close for the month. Karaoke and live music spots can operate only from 8.30pm to 1.30am.

Entertainment venues at star-rated hotels are allowed to remain open as they cater to the city's tourism industry.

In last Thursday's attack, hundreds of people raided and burnt down tens of houses in a red-light district in Pelalawan in the Riau regency, in Sumatra. The protesters said their action was part of an anti-vice campaign preceding the fasting month.

The attack took place after a demonstration by members of the local anti-vice movement, known as Gemas. Police were unable to stop the crowd from damaging the properties, the news agency said.

"The people have long warned red-light district operators to stop their activities but the warnings were ignored. This is the result of their arrogance," said Saidina Ali, an official of the local chapter of the Council of Ulama.