Indonesian police forcibly cut the hair of a group of transgender women and made them wear “male” clothing, authorities have said, amid a crackdown on the LGBT community in the world’s biggest Muslim-majority nation.

The incident happened after police raided several beauty salons in conservative Aceh province on Sunday and rounded up a dozen trans employees over claims they had teased a group of boys.

Police accused the employees of violating the province’s religious laws.

Dozens of locals tried to attack the group of beauticians as they were taken to the police station, but they were pushed back by authorities, they said.

Police then cut some of their long hair with scissors, as well as forcing them to wear “male” clothing and speak in “masculine” voices.

“We have reports from mothers that their sons were teased by the transgender women,” local police chief Ahmad Untung Surianata said.

“Their numbers are growing here – I don’t want that,” he added.

Surianata said the trans women would be held for “three days to give them counselling and coaching. It’s going well and now they are all acting like real men”.

Amnesty International’s Indonesia director, Usman Hamid, said: “The police’s so-called ‘re-education’ of transgender people is not only humiliating and inhumane, it is also unlawful and a clear breach of their human rights. Such incidents must be promptly and effectively investigated.”

Aceh on Sumatra island has been ruled by Islamic law since it was granted special autonomy in 2001 – an attempt by the central government to quell a long-running separatist insurgency.

This month a Christian was publicly flogged for selling alcohol in the conservative region, making him the third non-Muslim in Indonesia to suffer a public whipping.

Flogging is a common punishment under Aceh’s religious law and local police are also known to shave the heads of those accused of anti-social behaviour.

The trans women would be detained for several days, followed by a five-day “training” programme including efforts to make them walk and speak in a more “manly” way, as well as “morals teaching” by local clerics, police said.

“We want to change their mentality so they can be better people,” Surianata said.

Homosexuality and gay sex are legal everywhere in Indonesia except in Aceh. Prejudice against trans people, while widespread across the country, is particularly acute in the province.

Police have often used the country’s tough anti-pornography legislation to criminalise members of the LGBT community, and there has been a recent string of arrests.

“It’s very strange that officers [in Sunday’s incident] would arrest innocent people and cut off their hair,” said gay rights activist Hartoyo, who like many Indonesians goes by one name.

“It’s barbaric.”

Agence France-Presse in Banda Aceh