Police are urging the public to be vigilant against online blackmail of an intimate or sexual nature, commonly known as 'sextortion', following a surge in reported incidents.

Detective Inspector Hamill explained: "Typically, a person uses a false identity to befriend a victim via social media. The exchange may start with flirting or flattery, but ends with the victim coaxed into sending intimate images or performing sexual acts online, unwittingly in front of a camera.

"Behind the fake and attractive guise, there's a criminal. These people are often part of sophisticated and organised crime groups, mostly based overseas. They extort their victims by threatening to share those images or recordings unless demands for money are met."

She continued: "While we know that sextortion can affect anyone, the majority of victims are young men, aged between 18 and 23.

"Innocent people are left feeling humiliated and distraught, but the important message is that victims shouldn't let embarrassment stop them from reporting what's happened." The detective inspector added: "My message, in the first instance, is to be on your guard. Please be aware of the risks of sharing intimate images online, and if someone is pushing you to do this, then alarm bells should be ringing.

"But people do make mistakes, no one is infallible, and if you've been a victim of sextortion, then you're certainly not alone.

"Don't panic; don't respond to demands; and don't enter into further communication. If you can, confide in a trusted friend or family member, and please contact officers immediately on 101."

The Police Service has issued online safety advice, which includes:

Don't get lured or pushed into compromising situations. Trust your gut, and end uncomfortable situations immediately.

Always remember that what goes online may well stay online.

Be wary about whom you invite or accept invitations from on social networking sites. Do not accept friendship requests from complete strangers.

Update the privacy settings on your social networking accounts so only people you know can view your account. Do not include any sensitive or private information in profiles.

For further information and details of organisations who can help, visit www.psni.police.uk/sextortion