Enraged members of the militant Islamic Defenders Front raided a human rights workshop for ladyboys in Depok on Friday in the mistaken belief there was a lingerie contest taking place.

The attack by more than a dozen robe-clad hoodlums at the Hotel Bumi Wiyata in Depok, West Java, sent the about 25 ladyboys, known as waria, shrieking for cover.

Members of the group pounded tables with their fists and smashed plates, glasses and chairs as police tried to calm the situation. Television footage shows one of the officers being struck.

According to Detik.com, the embarrassed militants slowly slunk out of the room after failing to find any of the offending frilly underwear. "They suspected there was a contest, when in fact there was no contest," Comr. Ade Rahmat Idnal, chief detective with Depok Police, told the news portal.

The event in fact was a seminar held by the National Commission for Human Rights, which was educating the waria about the law and their human rights.

Ade said the shaken and "scared" waria had been successfully evacuated from the seminar without any injuries and taken to another location. Police did not say if they would charge the unwanted gatecrashers.