The BBC's Simon Ingram: Protesters were demanding the closure of brothels

Dozens of people were reportedly injured as protesters shouting Islamic slogans demanded the closure of bars and sex clubs during the Muslim fasting month of Ramadan.

Reports said the violence erupted on Friday when 5,000 demonstrators led by Muslim clerics marched into the red-light district.

Prostitution is illegal in Indonesia

Indonesian security forces managed to disperse the crowds after giving the club owners until Monday to suspend business for the rest of Ramadan.

Prostitution is illegal, but widely condoned, in Indonesia, where 90% of the population is Muslim.

Reports of the riot were not released until Sunday. Police said the Sumatran town had returned to calm, but security forces were patrolling on foot and in trucks.

Alcohol set on fire

Violence also flared in Sulawesi where thousands of people went on the rampage following reports that a drunken Christian had stabbed a Muslim during a quarrel.

Scores of people were injured and a disco was set on fire during rioting in the town of Poso on Friday and Saturday, officials said.

Mobs unloaded liquor from six shops and burned them on the street. They also damaged hotels and set their furniture on fire.

Government building torched

In a separate incident on the island, the daily Kompas newspaper reported that angry residents in the town of Jeneponto had set fire to the local parliament.

The attack followed allegations the new mayor had bribed legislators to award him the job.

Indonesia has been rocked by riots this year that reached a peak in May just before the ousting of its longtime authoritarian leader, President Suharto.

Religious and ethnic tensions have also been rising amid the political and economic turmoil.