The calls, made from overseas with a caller speaking in Mandarin with a China or Taiwanese accent, are typically made to offices and threatens to use violence to disrupt the victim's business activities or cause harm to family members if payments were not made.

The caller then demands a sum of money, claiming that it is needed to assist the victim's relative, who has allegedly murdered someone, to flee the country, and that the victim's family and company are being watched. The caller would threaten to harm them if his demands are not met.

Female victims have also been threatened with kidnapping and that the caller would take nude photos of them if they fail to comply with his demands.

The caller may also claim that he has links with secret societies and needs money to help his men escape Singapore after committing serious crimes, the police said.

In addition, the caller may also claim to be in possession of firearms and explosives and threaten to harm the victim and his business operations.

While the culprits have been unsuccessful so far and none of the threats made has been carried out, the police advise members of the public to be aware of and vigilant against such scams.

The police also advised members of the public not to reveal their personal details, including those of their business or family to the caller.

Members of the public should also not transfer money to unknown persons and report the case to the police as soon as possible by calling the police hotline 1800 - 255 0000 or 999 if urgent police assistance is needed.