A police raid at a Jalan Besar hotel in the early hours of yesterday resulted in the arrest of 23 women and a man.

The 24 people caught are believed to be sex workers who allegedly advertised sexual services ononline platforms and websites.

Preliminary investigations revealed that potential customers would book their services through mobile phone numbers or e-mail addresses provided online, said the police after the 61/2-hour operation.

The Straits Times witnessed the raid, which took place at about 5am.

Several plainclothes officerschecked the hotel guest list while others interviewed customers. The rest of the officers combed through most of the hotel's 70 rooms. About an hour later, the group was rounded up.

The police said those involved, all foreigners aged between 20 and 33, were believed to have made use of their stay in Singapore on valid social visit passes to allegedly commit vice offences.

The Straits Times understands that most of the women are from Thailand and the man is transgender. Some of those nabbed were believed to have been with clients when the authorities arrived. There were signs of forced entry on at least one door following the operation, which involved 36 officers from the Central Division and Criminal Investigation Department.

At about 6.30am, those arrested were led out of the four-storey hotel and taken away in four unmarked vehicles.