SINGAPORE - Four men and 11 women were arrested for online vice activities, police said.

The suspects, aged between 22 and 37, are allegedly involved in advertising the sexual services of female escorts online.

Officers from the Criminal Investigation Department raided six locations in Singapore in a 10-hour operation on Wednesday (Sept 14).

The locations are Geylang, Serangoon Road, Balestier Road, Orchard Road, Punggol Drive and Bayfront Avenue.

Cash of about $27,000, mobile phones and other documents were also seized during the operation.

Preliminary investigations revealed that the vice syndicate likely operated two websites advertising the sexual services of women escorts from Asean countries.

The four men will be charged under the Women's Charter, police said.

Under the Charter, any person who knowingly lives off on the earnings of the prostitution of another person can be jailed up to five years and fined up to $10,000.

Investigations against the remaining suspects are ongoing.

Superintendent of Police Tan Chi Koon said: "Vice operators who think that they can hide behind the anonymity of the Internet should think twice. The Police will find them and prosecute them to the fullest extent of the law."